2 # For a description of the syntax of this configuration file,
3 # see extra/config/Kconfig-language.txt
6 mainmenu "uClibc C Library Configuration"
8 config DESIRED_TARGET_ARCH
13 prompt "Target Architecture"
14 default TARGET_alpha if DESIRED_TARGET_ARCH = "alpha"
15 default TARGET_arm if DESIRED_TARGET_ARCH = "arm"
16 default TARGET_avr32 if DESIRED_TARGET_ARCH = "avr32"
17 default TARGET_bfin if DESIRED_TARGET_ARCH = "bfin"
18 default TARGET_cris if DESIRED_TARGET_ARCH = "cris"
19 default TARGET_e1 if DESIRED_TARGET_ARCH = "e1"
20 default TARGET_frv if DESIRED_TARGET_ARCH = "frv"
21 default TARGET_h8300 if DESIRED_TARGET_ARCH = "h8300"
22 default TARGET_hppa if DESIRED_TARGET_ARCH = "hppa"
23 default TARGET_i386 if DESIRED_TARGET_ARCH = "i386"
24 default TARGET_i960 if DESIRED_TARGET_ARCH = "i960"
25 default TARGET_ia64 if DESIRED_TARGET_ARCH = "ia64"
26 default TARGET_m68k if DESIRED_TARGET_ARCH = "m68k"
27 default TARGET_metag if DESIRED_TARGET_ARCH = "metag"
28 default TARGET_microblaze if DESIRED_TARGET_ARCH = "microblaze"
29 default TARGET_mips if DESIRED_TARGET_ARCH = "mips"
30 default TARGET_nios if DESIRED_TARGET_ARCH = "nios"
31 default TARGET_nios2 if DESIRED_TARGET_ARCH = "nios2"
32 default TARGET_powerpc if DESIRED_TARGET_ARCH = "powerpc"
33 default TARGET_sh if DESIRED_TARGET_ARCH = "sh"
34 default TARGET_sh64 if DESIRED_TARGET_ARCH = "sh64"
35 default TARGET_sparc if DESIRED_TARGET_ARCH = "sparc"
36 default TARGET_v850 if DESIRED_TARGET_ARCH = "v850"
37 default TARGET_vax if DESIRED_TARGET_ARCH = "vax"
38 default TARGET_x86_64 if DESIRED_TARGET_ARCH = "x86_64"
39 default TARGET_xtensa if DESIRED_TARGET_ARCH = "xtensa"
41 The architecture of your target.
88 config TARGET_microblaze
100 config TARGET_powerpc
127 menu "Target Architecture Features and Options"
130 source "extra/Configs/Config.alpha"
134 source "extra/Configs/Config.arm"
138 source "extra/Configs/Config.avr32"
142 source "extra/Configs/Config.bfin"
146 source "extra/Configs/Config.cris"
150 source "extra/Configs/Config.e1"
154 source "extra/Configs/Config.frv"
158 source "extra/Configs/Config.h8300"
162 source "extra/Configs/Config.hppa"
166 source "extra/Configs/Config.i386"
170 source "extra/Configs/Config.i960"
174 source "extra/Configs/Config.ia64"
178 source "extra/Configs/Config.m68k"
182 source "extra/Configs/Config.metag"
186 source "extra/Configs/Config.nios"
190 source "extra/Configs/Config.nios2"
194 source "extra/Configs/Config.microblaze"
198 source "extra/Configs/Config.mips"
202 source "extra/Configs/Config.powerpc"
206 source "extra/Configs/Config.sh"
210 source "extra/Configs/Config.sh64"
214 source "extra/Configs/Config.sparc"
218 source "extra/Configs/Config.v850"
222 source "extra/Configs/Config.vax"
226 source "extra/Configs/Config.x86_64"
230 source "extra/Configs/Config.xtensa"
234 source "extra/Configs/Config.c6x"
237 config TARGET_SUBARCH
239 default "e500" if CONFIG_E500
240 default "classic" if CONFIG_CLASSIC
241 default "sh4" if CONFIG_SH4
242 default "" if CONFIG_386
243 default "i486" if CONFIG_486
244 default "i586" if CONFIG_586
245 default "i686" if CONFIG_686
248 source "extra/Configs/Config.in.arch"
252 menu "General Library Settings"
258 bool "Generate only Position Independent Code (PIC)"
260 depends on !HAVE_NO_PIC
262 If you wish to build all of uClibc as PIC objects, then answer Y here.
263 If you are unsure, then you should answer N.
265 config ARCH_HAS_NO_SHARED
268 config ARCH_HAS_NO_LDSO
270 select ARCH_HAS_NO_SHARED
272 config ARCH_HAS_UCONTEXT
276 bool "Enable shared libraries"
277 depends on !ARCH_HAS_NO_SHARED
280 If you wish to build uClibc with support for shared libraries then
281 answer Y here. If you only want to build uClibc as a static library,
284 config FORCE_SHAREABLE_TEXT_SEGMENTS
285 bool "Only load shared libraries which can share their text segment"
286 depends on HAVE_SHARED
289 If you answer Y here, the uClibc native shared library loader will
290 only load shared libraries, which do not need to modify any
291 non-writable segments. These libraries haven't set the DT_TEXTREL
292 tag in the dynamic section (==> objdump).
293 All your libraries must be compiled with -fPIC or -fpic, and all
294 assembler function must be written as position independent code (PIC).
295 Enabling this option will make uClibc's shared library loader a
296 little bit smaller and guarantee that no memory will be wasted by
297 badly coded shared libraries.
299 config LDSO_LDD_SUPPORT
300 bool "Native 'ldd' support"
301 depends on HAVE_SHARED
304 Enable all the code needed to support traditional ldd,
305 which executes the shared library loader to resolve all dependencies
306 and then provide a list of shared libraries that are required for an
307 application to function. Disabling this option will make uClibc's
308 shared library loader a little bit smaller.
309 Most people will answer Y.
311 config LDSO_CACHE_SUPPORT
312 bool "Enable library loader cache (ld.so.conf)"
313 depends on HAVE_SHARED
316 Enable this to make use of /etc/ld.so.conf, the shared library loader
317 cache configuration file to support for non-standard library paths.
318 After updating this file, it is necessary to run 'ldconfig' to update
319 the /etc/ld.so.cache shared library loader cache file.
321 config LDSO_PRELOAD_ENV_SUPPORT
322 bool "Enable library loader LD_PRELOAD environment"
323 depends on HAVE_SHARED
326 Enable this to make use of LD_PRELOAD environment variable.
327 A whitespace-separated list of additional, user-specified, ELF shared
328 libraries to be loaded before all others. This can be used to
329 selectively override functions in other shared libraries. For
330 set-user-ID/set-group-ID ELF binaries, only libraries in the standard
331 search directories that are also set-user-ID will be loaded.
333 config LDSO_PRELOAD_FILE_SUPPORT
334 bool "Enable library loader preload file (ld.so.preload)"
335 depends on HAVE_SHARED
337 Enable this to make use of /etc/ld.so.preload. This file contains a
338 whitespace separated list of shared libraries to be loaded before
341 config LDSO_BASE_FILENAME
342 string "Shared library loader naming prefix"
343 depends on HAVE_SHARED && (LDSO_CACHE_SUPPORT || LDSO_PRELOAD_FILE_SUPPORT)
346 If you wish to support both uClibc and glibc on the same system, it
347 is necessary to set this to something other than "ld.so" to avoid
348 conflicts with glibc, which also uses "ld.so". This prevents both
349 libraries from using the same /etc/ld.so.* files. If you wish to
350 support both uClibc and glibc on the same system then you should set
351 this to "ld-uClibc.so".
353 Most people will leave this set to the default of "ld.so".
355 WARNING: Changing the default prefix could cause problems with
358 config LDSO_STANDALONE_SUPPORT
359 bool "Dynamic linker stand-alone mode support"
360 depends on HAVE_SHARED
362 The dynamic linker can be run either indirectly through running some
363 dynamically linked program or library (in which case no command line
364 options to the dynamic linker can be passed and, in the ELF case, the
365 dynamic linker which is stored in the .interp section of the program
366 is executed) or directly by running:
368 /lib/ld-uClibc.so.* [OPTIONS] [PROGRAM [ARGUMENTS]]
370 Stand-alone execution is a prerequisite for adding prelink
371 capabilities to uClibc dynamic linker, as well useful for testing an
372 updated version of the dynamic linker without breaking the system.
374 config LDSO_PRELINK_SUPPORT
375 bool "Dynamic linker prelink support"
376 depends on HAVE_SHARED
377 select LDSO_STANDALONE_SUPPORT
379 The dynamic linker can be used in stand-alone mode by the prelink tool
380 for prelinking ELF shared libraries and binaries to speed up startup
381 time. It also is able to load and handle prelinked libraries and
384 config UCLIBC_STATIC_LDCONFIG
385 bool "Link ldconfig statically"
386 depends on HAVE_SHARED
389 Enable this option to statically link the ldconfig binary.
391 Making ldconfig static can be beneficial if you have a library
392 problem and need to use ldconfig to recover. Sometimes it is
393 preferable to instead keep the size of the system down, in which
394 case you should disable this option.
397 bool "Enable ELF RUNPATH tag support"
398 depends on HAVE_SHARED
399 default y if LDSO_CACHE_SUPPORT
401 ELF's may have dynamic RPATH/RUNPATH tags. These tags list paths
402 which extend the library search paths. They are really only useful
403 if a package installs libraries in non standard locations and
404 ld.so.conf support is disabled.
406 Usage of RUNPATH tags is not too common, so disabling this feature
407 should be safe for most people.
409 config LDSO_SAFE_RUNPATH
410 bool "Allow only RUNPATH beginning with /"
411 depends on LDSO_RUNPATH
414 Allow only absolute path in RPATH/RUNPATH.
416 config LDSO_SEARCH_INTERP_PATH
417 bool "Add ldso path to lib search path"
418 depends on HAVE_SHARED
421 The ldso is told where it is being executed from and can use that
422 path to find related core libraries. This is useful by default,
423 but can be annoying in a mixed development environment.
425 i.e. if the ldso is run from /foo/boo/ldso.so, it will start its
426 library search with /foo/boo/
428 If unsure, simply say Y here.
430 config LDSO_LD_LIBRARY_PATH
431 bool "Add LD_LIBRARY_PATH to lib search path"
432 depends on HAVE_SHARED
435 On hardened system it could be useful to disable the use of
436 LD_LIBRARY_PATH environment variable (a colon-separated list of
437 directories in which to search for ELF libraries at execution-time).
439 If unsure, simply say Y here.
441 config LDSO_NO_CLEANUP
442 bool "Disable automatic unloading of dynamically loaded shared objects"
443 depends on HAVE_SHARED
445 If you need complete allocation traces when debugging memory leaks
446 using Valgrind in a process that dynamically loads shared objects,
447 then answer Y here. Unlike glibc, uClibc unloads all dynamically
448 loaded shared objects when a process exits, which prevents Valgrind
449 from correctly resolving the symbols from the unloaded shared objects.
450 Unless you know you need this, you should answer N.
452 config UCLIBC_CTOR_DTOR
453 bool "Support global constructors and destructors"
456 If you wish to build uClibc with support for global constructor
457 (ctor) and global destructor (dtor) support, then answer Y here.
458 When ctor/dtor support is enabled, binaries linked with uClibc must
459 also be linked with crtbegin.o and crtend.o which are provided by gcc
460 (the "*startfile:" and "*endfile:" settings in your gcc specs file
461 may need to be adjusted to include these files). This support will
462 also add a small amount of additional size to each binary compiled vs
463 uClibc. If you will be using uClibc with C++, or if you need the gcc
464 __attribute__((constructor)) and __attribute__((destructor)) to work,
465 then you definitely want to answer Y here. If you don't need ctors
466 or dtors and want your binaries to be as small as possible, then
469 config LDSO_GNU_HASH_SUPPORT
470 bool "Enable GNU hash style support"
471 depends on HAVE_SHARED
473 Newest binutils support a new hash style named GNU-hash. The dynamic
474 linker will use the new GNU-hash section (.gnu.hash) for symbol lookup
475 if present into the ELF binaries, otherwise it will use the old SysV
476 hash style (.hash). This ensures that it is completely backward
478 Further, being the hash table implementation self-contained into each
479 executable and shared libraries, objects with mixed hash style can
480 peacefully coexist in the same process.
482 If you want to use this new feature, answer Y
485 prompt "Thread support"
486 #default UCLIBC_HAS_THREADS_NATIVE if (TARGET_alpha || TARGET_arm || TARGET_i386 || TARGET_mips || TARGET_powerpc || TARGET_sh || TARGET_sh64)
487 default HAS_NO_THREADS
489 If you want to compile uClibc with pthread support, then answer Y.
490 This will increase the size of uClibc by adding a bunch of locking
491 to critical data structures, and adding extra code to ensure that
492 functions are properly reentrant.
494 config HAS_NO_THREADS
497 Disable thread support.
499 config LINUXTHREADS_OLD
500 bool "older (stable) version of linuxthreads"
501 # linuxthreads and linuxthreads.old need nanosleep()
502 select UCLIBC_HAS_REALTIME
504 There are two versions of linuxthreads. The older (stable) version
505 has been in uClibc for quite a long time but hasn't seen too many
506 updates other than bugfixes.
509 config LINUXTHREADS_NEW
510 bool "slightly newer version of linuxthreads"
511 depends on ARCH_HAS_DEPRECATED_SYSCALLS
513 The new version has not been tested much, and lacks ports for arches
514 which glibc does not support (like bfin/frv/etc...), but is based on
515 the latest code from glibc, so it may be the only choice for the
516 newer ports (like alpha/amd64/64bit arches and hppa).
518 config UCLIBC_HAS_THREADS_NATIVE
519 bool "Native POSIX Threading (NPTL)"
520 select UCLIBC_HAS_TLS
521 select UCLIBC_HAS_STDIO_FUTEXES
522 select UCLIBC_HAS_REALTIME
523 # i386 has no lowlevellock support (yet) as opposed to i486 onward
524 depends on !CONFIG_386
526 If you want to compile uClibc with NPTL support, then answer Y.
528 IMPORTANT NOTE! NPTL requires a Linux 2.6 kernel, binutils
529 at least version 2.16 and GCC with at least version 4.1.0. NPTL
530 will not work with older versions of any above sources. If you
531 ignore any of these guidelines, you do so at your own risk. Do
532 not ask for help on any of the development mailing lists.
534 !!!! WARNING !!!! BIG FAT WARNING !!!! REALLY BIG FAT WARNING !!!!
536 This is experimental code and at times it may not even build and
537 even if it does it might decide to do random damage. This code is
538 potentially hazardous to your health and sanity. It will remain
539 that way until further notice at which point this notice will
540 disappear. Thank you for your support and for not smoking.
544 config UCLIBC_HAS_THREADS
545 def_bool y if !HAS_NO_THREADS
547 config UCLIBC_HAS_TLS
548 bool "Thread-Local Storage"
549 depends on UCLIBC_HAS_THREADS_NATIVE
551 If you want to enable TLS support then answer Y.
552 This is fast an efficient way to store per-thread local data
553 which is not on stack. It needs __thread support enabled in
556 config PTHREADS_DEBUG_SUPPORT
557 bool "Build pthreads debugging support"
558 depends on UCLIBC_HAS_THREADS
560 Say Y here if you wish to be able to debug applications that use
561 uClibc's pthreads library. By enabling this option, a library
562 named libthread_db will be built. This library will be dlopen()'d
563 by gdb and will allow gdb to debug the threads in your application.
565 IMPORTANT NOTE! Because gdb must dlopen() the libthread_db library,
566 you must compile gdb with uClibc in order for pthread debugging to
569 If you are doing development and want to debug applications using
570 uClibc's pthread library, answer Y. Otherwise, answer N.
573 config UCLIBC_HAS_SYSLOG
574 bool "Syslog support"
576 depends on UCLIBC_HAS_NETWORK_SUPPORT
577 select UCLIBC_HAS_SOCKET
579 Support sending messages to the system logger.
580 This requires socket-support.
582 config UCLIBC_HAS_LFS
583 bool "Large File Support"
586 If you wish to build uClibc with support for accessing large files
587 (i.e. files greater then 2 GiB) then answer Y. Do not enable this
588 if you are using an older Linux kernel (2.0.x) that lacks large file
589 support. Enabling this option will increase the size of uClibc.
592 prompt "Malloc Implementation"
593 default MALLOC if ! ARCH_USE_MMU
594 default MALLOC_STANDARD if ARCH_USE_MMU
599 "malloc" use mmap for all allocations and so works very well on
600 MMU-less systems that do not support the brk() system call. It is
601 pretty smart about reusing already allocated memory, and minimizing
603 This is the default for uClinux MMU-less systems.
608 "malloc-simple" is trivially simple and slow as molasses. It
609 was written from scratch for uClibc, and is the simplest possible
610 (and therefore smallest) malloc implementation.
612 This uses only the mmap() system call to allocate and free memory,
613 and does not use the brk() system call at all, making it a fine
614 choice for MMU-less systems with very limited memory. It's 100%
615 standards compliant, thread safe, very small, and releases freed
616 memory back to the OS immediately rather than keeping it in the
617 process's heap for reallocation. It is also VERY SLOW.
619 config MALLOC_STANDARD
620 bool "malloc-standard"
621 depends on ARCH_USE_MMU
623 "malloc-standard" is derived from the public domain dlmalloc
624 implementation by Doug Lea. It is quite fast, and is pretty smart
625 about reusing already allocated memory, and minimizing memory
626 wastage. This uses brk() for small allocations, while using mmap()
627 for larger allocations. This is the default malloc implementation
630 If unsure, answer "malloc-standard".
634 config MALLOC_GLIBC_COMPAT
635 bool "Malloc returns live pointer for malloc(0)"
637 The behavior of malloc(0) is listed as implementation-defined by
638 SuSv3. Glibc returns a valid pointer to something, while uClibc
639 normally returns NULL. I personally feel glibc's behavior is
640 not particularly safe, and allows buggy applications to hide very
643 When this option is enabled, uClibc will act just like glibc, and
644 return a live pointer when someone calls malloc(0). This pointer
645 provides a malloc'ed area with a size of 1 byte. This feature is
646 mostly useful when dealing with applications using autoconf's broken
647 AC_FUNC_MALLOC macro (which redefines malloc as rpl_malloc if it
648 does not detect glibc style returning-a-valid-pointer-for-malloc(0)
649 behavior). Most people can safely answer N.
651 config UCLIBC_HAS_OBSTACK
652 bool "Obstack Support (gnu extension)"
654 When this option is enabled, uClibc will provide support for obstacks.
655 An obstack is a structure in which memory can be dynamically allocated
656 as a 'stack of objects'. Many programs need this GNU extention and
657 you should say Y if you are using any. Otherwise, say N to save some
660 config UCLIBC_DYNAMIC_ATEXIT
661 bool "Dynamic atexit() Support"
664 When this option is enabled, uClibc will support an infinite number,
665 of atexit() and on_exit() functions, limited only by your available
666 memory. This can be important when uClibc is used with C++, since
667 global destructors are implemented via atexit(), and it is quite
668 possible to exceed the default number when this option is disabled.
669 Enabling this option adds a few bytes, and more significantly makes
670 atexit and on_exit depend on malloc, which can be bad when compiling
673 Unless you use uClibc with C++, you should probably answer N.
676 bool "Old (visible) atexit Support"
678 Enable this option if you want to update from 0.9.28 to git/0.9.29,
679 else you will be missing atexit() until you rebuild all apps.
681 config UCLIBC_SUSV2_LEGACY
682 bool "Enable SuSv2 LEGACY functions"
684 Enable this option if you want to have SuSv2 LEGACY functions
685 Currently applies to:
689 WARNING! ABI incompatibility.
691 config UCLIBC_SUSV3_LEGACY
692 bool "Enable SuSv3 LEGACY functions"
698 Enable this option if you want to have SuSv3 LEGACY functions
699 in the library, else they are replaced by SuSv3 proposed macros.
700 Currently applies to:
702 bcmp, bcopy, bzero, index, rindex, ftime,
703 bsd_signal, (ecvt), (fcvt), gcvt, (getcontext),
704 (getwd), (makecontext),
705 mktemp, (pthread_attr_getstackaddr), (pthread_attr_setstackaddr),
706 scalb, (setcontext), (swapcontext), ualarm, usleep,
709 WARNING! ABI incompatibility.
711 config UCLIBC_HAS_CONTEXT_FUNCS
712 bool "Use obsolescent context control functions"
713 depends on UCLIBC_SUSV3_LEGACY && ARCH_HAS_UCONTEXT
715 Add into library the SuSv3 obsolescent functions used for context
716 control. The setcontext family allows the implementation in C of
717 advanced control flow patterns such as iterators, fibers, and
718 coroutines. They may be viewed as an advanced version of
719 setjmp/longjmp; whereas the latter allows only a single non-local jump
720 up the stack, setcontext allows the creation of multiple cooperative
721 threads of control, each with its own stack.
722 These functions are: setcontext, getcontext, makecontext, swapcontext.
724 config UCLIBC_SUSV3_LEGACY_MACROS
725 bool "Enable SuSv3 LEGACY macros"
727 Enable this option if you want to have SuSv3 LEGACY macros.
728 Currently applies to bcopy/bzero/bcmp/index/rindex et al.
729 WARNING! ABI incompatibility.
731 config UCLIBC_SUSV4_LEGACY
732 bool "Enable SuSv4 LEGACY or obsolescent functions"
734 Enable this option if you want to have SuSv4 LEGACY functions
735 and macros in the library.
736 Currently applies to:
739 _longjmp, _setjmp, _tolower, _toupper, ftw, getitimer,
740 gettimeofday, isascii, pthread_getconcurrency,
741 pthread_setconcurrency, setitimer, setpgrp, sighold,
742 sigignore, sigpause, sigrelse, sigset, siginterrupt,
743 tempnam, toascii, ulimit.
746 asctime, asctime_r, ctime, ctime_r, gets, rand_r,
749 WARNING! ABI incompatibility.
751 config UCLIBC_STRICT_HEADERS
752 bool "Hide structures and constants for unsupported features"
754 Hide structures and constants in headers that should not be used,
755 because the respective feature is disabled.
757 WARNING! enabling this option requires to patch many faulty apps,
758 since they make (wrongly) use of these structures/constants,
759 although the feature was disabled.
761 config UCLIBC_HAS_STUBS
762 bool "Provide stubs for unavailable functionality"
764 With this option uClibc provides non-functional stubs for
765 functions which are impossible to implement on the target
766 architecture. Otherwise, such functions are simply omitted.
768 config UCLIBC_HAS_SHADOW
769 bool "Shadow Password Support"
772 Answer N if you do not need shadow password support.
773 Most people will answer Y.
775 config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
776 bool "Support for program_invocation_name"
778 Support for the GNU-specific program_invocation_name and
779 program_invocation_short_name strings. Some GNU packages
780 (like tar and coreutils) utilize these for extra useful
781 output, but in general are not required.
783 At startup, these external strings are automatically set
784 up based on the value of ARGV[0].
786 If unsure, just answer N.
788 config UCLIBC_HAS___PROGNAME
789 bool "Support for __progname"
792 Some packages (like openssh) like to peek into internal libc
793 symbols to make their output a bit more user friendly.
795 At startup, __progname is automatically set up based on the
798 If unsure, just answer N.
800 config UCLIBC_HAS_PTY
801 bool "Support for pseudo-terminals"
804 This enables support for pseudo-terminals (see man 4 pts
807 If unsure, just answer Y.
810 bool "Assume that /dev/pts is a devpts or devfs file system"
812 depends on UCLIBC_HAS_PTY
814 Enable this if /dev/pts is on a devpts or devfs filesystem. Both
815 these filesystems automatically manage permissions on the /dev/pts
816 devices. You may need to mount your devpts or devfs filesystem on
817 /dev/pts for this to work.
819 Most people should answer Y.
821 config UNIX98PTY_ONLY
822 bool "Support only Unix 98 PTYs"
824 depends on UCLIBC_HAS_PTY
826 If you want to support only Unix 98 PTYs enable this. Some older
827 applications may need this disabled and will thus use legacy BSD
828 style PTY handling which is more complex and also bigger than
829 Unix 98 PTY handling.
831 For most current programs, you can generally answer Y.
834 config UCLIBC_HAS_GETPT
835 bool "Support getpt() (glibc-compat)"
836 depends on UCLIBC_HAS_PTY
838 Some packages may need getpt().
839 All of those are non-standard and can be considered
840 GNU/libc compatibility.
841 Either use posix_openpt() or just open /dev/ptmx yourself.
843 If unsure, just say N.
847 # Have to use __libc_ptyname{1,2}[] and related bloat
848 config UCLIBC_HAS_GETPT
852 config UCLIBC_HAS_LIBUTIL
853 bool "Provide libutil library and functions"
854 depends on UCLIBC_HAS_PTY
856 Provide a libutil library.
857 This non-standard conforming library provides the following
860 forkpty(): combines openpty(), fork(2), and login_tty() to
861 create a new process operating in a pseudo-terminal.
862 login(): write utmp and wtmp entries
863 login_tty(): prepares for a login on the tty fd by creating a
864 new session, making fd the controlling terminal for
865 the calling process, setting fd to be the standard
866 input, output, and error streams of the current
867 process, and closing fd.
868 logout(): write utmp and wtmp entries
869 logwtmp(): constructs a utmp structure and calls updwtmp() to
870 append the structure to the utmp file.
871 openpty(): finds an available pseudo-terminal and returns
872 file descriptors for the master and slave
874 This library adds about 3k-4k to your system.
876 config UCLIBC_HAS_TM_EXTENSIONS
877 bool "Support 'struct tm' timezone extension fields"
880 Enabling this option adds fields to 'struct tm' in time.h for
881 tracking the number of seconds east of UTC, and an abbreviation for
882 the current timezone. These fields are not specified by the SuSv3
883 standard, but they are commonly used in both GNU and BSD application
886 To strictly follow the SuSv3 standard, leave this disabled.
887 Most people will probably want to answer Y.
889 config UCLIBC_HAS_TZ_CACHING
890 bool "Enable caching of the last valid timezone 'TZ' string"
893 Answer Y to enable caching of the last valid 'TZ' string describing
894 the timezone setting. This allows a quick string compare to avoid
895 repeated parsing of unchanged 'TZ' strings when tzset() is called.
897 Most people will answer Y.
899 config UCLIBC_HAS_TZ_FILE
900 bool "Enable '/etc/TZ' file support to set a default timezone (uClibc-specific)"
903 Answer Y to enable the setting of a default timezone for uClibc.
905 Ordinarily, uClibc gets the timezone information exclusively from the
906 'TZ' environment variable. In particular, there is no support for
907 the zoneinfo directory tree or the /etc/timezone file used by glibc.
909 With this option enabled, uClibc will use the value stored in the
910 file '/etc/TZ' (default path) to obtain timezone information if the
911 'TZ' environment variable is missing or has an invalid value. The
912 file consists of a single line (newline required) of text describing
913 the timezone in the format specified for the TZ environment variable.
915 Doing 'echo CST6CDT > /etc/TZ' is enough to create a valid file.
917 http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
918 for details on valid settings of 'TZ'.
920 Most people will answer Y.
922 config UCLIBC_HAS_TZ_FILE_READ_MANY
923 bool "Repeatedly read the '/etc/TZ' file"
924 depends on UCLIBC_HAS_TZ_FILE
927 Answer Y to enable repeated reading of the '/etc/TZ' file even after
928 a valid value has been read. This incurs the overhead of an
929 open/read/close for each tzset() call (explicit or implied). However,
930 setting this will allow applications to update their timezone
931 information if the contents of the file change.
933 Most people will answer Y.
935 config UCLIBC_TZ_FILE_PATH
936 string "Path to the 'TZ' file for setting the global timezone"
937 depends on UCLIBC_HAS_TZ_FILE
940 This is the path to the 'TZ' file.
942 Most people will use the default of '/etc/TZ'.
944 config UCLIBC_FALLBACK_TO_ETC_LOCALTIME
945 bool "Use /etc/localtime as a fallback"
946 depends on UCLIBC_HAS_TZ_FILE
949 Answer Y to try to use /etc/localtime file.
950 On glibc systems this file (if it is in TZif2 format)
951 contains timezone string at the end.
953 Most people will answer Y.
957 menu "Advanced Library Settings"
959 config UCLIBC_PWD_BUFFER_SIZE
960 int "Buffer size for getpwnam() and friends"
964 This sets the value of the buffer size for getpwnam() and friends.
965 By default, this is 256. (For reference, glibc uses 1024).
966 The value can be found using sysconf() with the _SC_GETPW_R_SIZE_MAX
969 config UCLIBC_GRP_BUFFER_SIZE
970 int "Buffer size for getgrnam() and friends"
974 This sets the value of the buffer size for getgrnam() and friends.
975 By default, this is 256. (For reference, glibc uses 1024).
976 The value can be found using sysconf() with the _SC_GETGR_R_SIZE_MAX
979 comment "Support various families of functions"
981 config UCLIBC_LINUX_MODULE_26
982 bool "Linux kernel module functions (2.6)"
985 delete_module, init_module
986 are used in linux for loadable kernel modules.
988 Say N if you do not use kernel modules.
990 config UCLIBC_LINUX_MODULE_24
991 bool "Linux kernel module functions (<2.6)"
992 depends on !TARGET_bfin && !TARGET_c6x
994 create_module, query_module
995 are used in linux (prior to 2.6) for loadable kernel modules.
997 Say N if you do not use kernel modules, or you only support
1000 config UCLIBC_LINUX_SPECIFIC
1001 bool "Linux specific functions"
1004 accept4(), bdflush(),
1005 capget(), capset(), eventfd(), fstatfs(),
1006 inotify_*(), ioperm(), iopl(),
1007 madvise(), modify_ldt(), pipe2(), personality(),
1008 prctl()/arch_prctl(), pivot_root(), modify_ldt(),
1009 ppoll(), readahead(), reboot(), remap_file_pages(),
1010 sched_getaffinity(), sched_setaffinity(), sendfile(),
1011 setfsgid(), setfsuid(), setresgid(), setresuid(),
1012 splice(), vmsplice(), tee(), signalfd(), swapoff(), swapon(),
1013 sync_file_range(), _sysctl(), sysinfo(), timerfd_*(), vhangup(),
1016 config UCLIBC_HAS_GNU_ERROR
1017 bool "Support GNU extensions for error-reporting"
1020 Support for the GNU-specific error(), error_at_line(),
1021 void (* error_print_progname)(), error_message_count
1022 functions and variables. Some GNU packages
1023 utilize these for extra useful output, but in general
1026 If unsure, just answer N.
1028 config UCLIBC_BSD_SPECIFIC
1029 bool "BSD specific functions"
1032 mincore(), getdomainname(), setdomainname()
1036 config UCLIBC_HAS_BSD_ERR
1037 bool "BSD err functions"
1040 These functions are non-standard BSD extensions.
1041 err(), errx(), warn(), warnx(), verr(), verrx(), vwarn(), vwarnx()
1045 config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
1046 bool "BSD obsolete signal functions"
1048 These functions are provided as a compatibility interface for
1049 programs that make use of the historical System V signal API.
1050 This API is obsolete:
1051 new applications should use the POSIX signal API (sigaction(2),
1052 sigprocmask(2), etc.).
1055 sigset(), sighold(), sigrelse(), sigignore()
1059 config UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL
1060 bool "SYSV obsolete signal functions"
1062 Use of sysv_signal() should be avoided; use sigaction(2) instead.
1066 config UCLIBC_NTP_LEGACY
1067 bool "ntp_*() aliases"
1069 Provide legacy aliases for ntp functions:
1070 ntp_adjtime(), ntp_gettime()
1072 It is safe to say N here.
1074 config UCLIBC_SV4_DEPRECATED
1075 bool "Enable SVr4 deprecated functions"
1077 These functions are DEPRECATED in System V release 4.
1078 Say N unless you desparately need one of the functions below:
1080 ustat() [use statfs(2) in your code instead]
1082 config UCLIBC_HAS_REALTIME
1083 bool "Realtime-related family of SUSv functions"
1086 These functions are part of the Timers option and need not
1087 be available on all implementations.
1088 Includes AIO, message-queue, scheduler, semaphore functions:
1103 clock_getres(), clock_gettime(), clock_settime()
1105 mlockall(), munlockall()
1117 sched_get_priority_max(), sched_get_priority_min()
1118 sched_getscheduler()
1119 sched_rr_get_interval()
1121 sched_setscheduler()
1128 sem_trywait(), sem_wait()
1131 sigtimedwait(), sigwaitinfo()
1134 timer_getoverrun(), timer_gettime(), timer_settime()
1136 config UCLIBC_HAS_ADVANCED_REALTIME
1137 bool "Advanced realtime-related family of SUSv functions"
1139 depends on UCLIBC_HAS_REALTIME
1141 These functions are part of the Timers option and need not
1142 be available on all implementations.
1144 clock_getcpuclockid()
1153 posix_spawnattr_destroy(), posix_spawnattr_init()
1154 posix_spawnattr_getflags(), posix_spawnattr_setflags()
1155 posix_spawnattr_getpgroup(), posix_spawnattr_setpgroup()
1156 posix_spawnattr_getschedparam(), posix_spawnattr_setschedparam()
1157 posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedpolicy()
1158 posix_spawnattr_getsigdefault(), posix_spawnattr_setsigdefault()
1159 posix_spawnattr_getsigmask(), posix_spawnattr_setsigmask()
1160 posix_spawn_file_actions_addclose()
1161 posix_spawn_file_actions_adddup2()
1162 posix_spawn_file_actions_addopen()
1163 posix_spawn_file_actions_destroy()
1164 posix_spawn_file_actions_init()
1167 posix_typed_mem_get_info()
1168 pthread_mutex_timedlock()
1171 #config UCLIBC_HAS_TERMIOS
1172 # bool "termios functions"
1175 # Get and set terminal attributes, line control, get and set baud
1177 # termios(), tcgetattr(), tcsetattr(), tcsendbreak(), tcdrain(),
1178 # tcflush(), tcflow(), cfmakeraw(), cfgetospeed(), cfgetispeed(),
1179 # cfsetispeed(), cfsetospeed(), cfsetspeed()
1183 config UCLIBC_HAS_EPOLL
1187 epoll_create(), epoll_ctl(), epoll_wait() functions.
1189 config UCLIBC_HAS_XATTR
1190 bool "Extended Attributes"
1193 Extended Attributes support.
1208 Say N unless you need support for extended attributes and the
1209 filesystems do actually support them.
1211 config UCLIBC_HAS_PROFILING
1212 bool "Profiling support"
1215 gcc's -finstrument-functions needs these.
1217 Most people can safely answer N.
1219 config UCLIBC_HAS_CRYPT_IMPL
1220 bool "libcrypt support"
1223 libcrypt contains crypt(), setkey() and encrypt()
1225 config UCLIBC_HAS_SHA256_CRYPT_IMPL
1226 bool "libcrypt SHA256 support"
1227 depends on UCLIBC_HAS_CRYPT_IMPL
1229 This adds support for SHA256 password hashing via the crypt() function.
1230 Say N here if you do not need SHA256 crypt support.
1232 config UCLIBC_HAS_SHA512_CRYPT_IMPL
1233 bool "libcrypt SHA512 support"
1234 depends on UCLIBC_HAS_CRYPT_IMPL
1236 This adds support for SHA512 password hashing via the crypt() function.
1237 Say N here if you do not need SHA512 crypt support.
1239 config UCLIBC_HAS_CRYPT_STUB
1240 bool "libcrypt stubs"
1242 depends on !UCLIBC_HAS_CRYPT_IMPL
1244 Standards mandate that crypt(3) provides a stub if it is unavailable.
1245 If you enable this option then stubs for
1246 crypt(), setkey() and encrypt()
1247 will be provided in a small libcrypt.
1249 config UCLIBC_HAS_CRYPT
1251 depends on UCLIBC_HAS_CRYPT_IMPL || UCLIBC_HAS_CRYPT_STUB
1254 menuconfig UCLIBC_HAS_NETWORK_SUPPORT
1255 bool "Networking Support"
1258 Say N here if you do not need network support.
1260 if UCLIBC_HAS_NETWORK_SUPPORT
1261 config UCLIBC_HAS_SOCKET
1262 bool "Socket support"
1265 If you want to include support for sockets then answer Y.
1267 config UCLIBC_HAS_IPV4
1268 bool "IP version 4 support"
1270 select UCLIBC_HAS_SOCKET
1272 If you want to include support for the Internet Protocol
1273 (IP version 4) then answer Y.
1275 Most people will say Y.
1277 config UCLIBC_HAS_IPV6
1278 bool "IP version 6 support"
1279 select UCLIBC_HAS_SOCKET
1281 If you want to include support for the next version of the Internet
1282 Protocol (IP version 6) then answer Y.
1284 Most people should answer N.
1286 config UCLIBC_HAS_RPC
1287 bool "Remote Procedure Call (RPC) support"
1288 # RPC+socket-ipvX doesn't currently work.
1289 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1291 If you want to include RPC support, enable this. RPC is rarely used
1292 for anything except for the NFS filesystem. Unless you plan to use
1293 NFS, you can probably leave this set to N and save some space.
1295 If you need to use NFS then you should answer Y.
1297 config UCLIBC_HAS_FULL_RPC
1298 bool "Full RPC support"
1299 depends on UCLIBC_HAS_RPC
1300 default y if !HAVE_SHARED
1302 Normally we enable just enough RPC support for things like rshd and
1303 nfs mounts to work. If you find you need the rest of the RPC stuff,
1304 then enable this option. Most people can safely answer N.
1306 config UCLIBC_HAS_REENTRANT_RPC
1307 bool "Reentrant RPC support"
1308 depends on UCLIBC_HAS_RPC
1309 default y if !HAVE_SHARED
1311 Most packages utilize the normal (non-reentrant) RPC functions, but
1312 some (like exportfs from nfs-utils) need these reentrant versions.
1314 Most people can safely answer N.
1316 config UCLIBC_USE_NETLINK
1317 bool "Use netlink to query interfaces"
1318 depends on UCLIBC_HAS_SOCKET
1320 In newer versions of Linux (2.4.17+), support was added for querying
1321 network device information via netlink rather than the old style
1322 ioctl's. Most of the time, the older ioctl style is sufficient (and
1323 it is smaller than netlink), but if you find that not all of your
1324 devices are being returned by the if_nameindex() function, you will
1325 have to use the netlink implementation.
1327 Most people can safely answer N.
1329 config UCLIBC_SUPPORT_AI_ADDRCONFIG
1330 bool "Support the AI_ADDRCONFIG flag"
1331 depends on UCLIBC_USE_NETLINK
1333 The implementation of AI_ADDRCONFIG is aligned with the glibc
1334 implementation using netlink to query interfaces to find both
1335 ipv4 and ipv6 support. This is only needed if an application uses
1336 the AI_ADDRCONFIG flag.
1338 Most people can safely answer N.
1340 config UCLIBC_HAS_BSD_RES_CLOSE
1341 bool "Support res_close() (bsd-compat)"
1343 Answer Y if you desperately want to support BSD compatibility in
1346 Most people will say N.
1348 config UCLIBC_HAS_COMPAT_RES_STATE
1349 bool "Use compatible but bloated _res"
1352 Answer Y if you build network utilities and they muck with resolver
1353 internals a lot (_res global structure). uclibc does not use most
1354 of _res.XXX fields, and with this option OFF they won't even exist.
1355 Which will make e.g. dig build fail.
1356 Answering N saves around 400 bytes in bss.
1358 config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
1359 bool "Use extra compatible but extra bloated _res"
1361 Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
1362 As far as I can say, this should never be needed.
1364 config UCLIBC_HAS_RESOLVER_SUPPORT
1365 bool "DNS resolver functions"
1366 select UCLIBC_HAS_COMPAT_RES_STATE
1367 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1369 Provide implementations for DNS resolver functions.
1370 In particular, the following functions will be added to the
1373 ns_skiprr, ns_initparse, ns_parserr, ns_msg_getflag,
1374 res_mkquery, res_init, res_ninit, res_close, res_nclose
1375 res_query, res_search, res_querydomain,
1377 ns_name_uncompress, ns_name_ntop, ns_name_pton, ns_name_unpack,
1378 ns_name_pack, ns_name_compress, ns_name_skip, dn_skipname,
1379 ns_get16, ns_get32, ns_put16, ns_put32
1381 config UCLIBC_HAS_LIBRESOLV_STUB
1382 bool "Provide libresolv stub"
1384 Provide a dummy resolv library.
1386 config UCLIBC_HAS_LIBNSL_STUB
1387 bool "Provide libnsl stub"
1389 Provide a dummy nsl library.
1394 menu "String and Stdio Support"
1396 config UCLIBC_HAS_STRING_GENERIC_OPT
1397 bool "Use faster (but larger) generic string functions"
1400 Answer Y to use the (tweaked) glibc generic string functions.
1402 In general, they are faster (but 3-5K larger) than the base
1403 uClibc string functions which are optimized solely for size.
1405 Many people will answer Y.
1407 config UCLIBC_HAS_STRING_ARCH_OPT
1408 bool "Use arch-specific assembly string functions (where available)"
1411 Answer Y to use any archtecture-specific assembly language string
1412 functions available for this target plaform.
1414 Note that assembly implementations are not available for all string
1415 functions, so some generic (written in C) string functions may
1418 These are small and fast, the only reason _not_ to say Y here is
1419 for debugging purposes.
1421 config UCLIBC_HAS_CTYPE_TABLES
1422 bool "Use Table Versions Of 'ctype.h' Functions."
1425 Answer Y to use table versions of the 'ctype.h' functions.
1426 While the non-table versions are often smaller when building
1427 statically linked apps, they work only in stub locale mode.
1429 Most people will answer Y.
1431 config UCLIBC_HAS_CTYPE_SIGNED
1432 bool "Support Signed Characters In 'ctype.h' Functions."
1433 depends on UCLIBC_HAS_CTYPE_TABLES
1436 Answer Y to enable support for passing signed char values to
1437 the 'ctype.h' functions. ANSI/ISO C99 and SUSv3 specify that
1438 these functions are only defined for unsigned char values and
1439 EOF. However, glibc allows negative signed char values as well
1440 in order to support 'broken old programs'.
1442 Most people will answer Y.
1445 prompt "ctype argument checking"
1446 depends on UCLIBC_HAS_CTYPE_TABLES
1447 default UCLIBC_HAS_CTYPE_UNSAFE
1449 Please select the invalid arg behavior you want for the 'ctype'
1452 The 'ctype' functions are now implemented using table lookups, with
1453 the arg being the index. This can result in incorrect memory accesses
1454 or even segfaults for args outside of the allowed range.
1456 NOTE: This only affects the 'ctype' _functions_. It does not affect
1457 the macro implementations.
1459 config UCLIBC_HAS_CTYPE_UNSAFE
1460 bool "Do not check -- unsafe"
1462 config UCLIBC_HAS_CTYPE_CHECKED
1463 bool "Detect and handle appropriately"
1465 config UCLIBC_HAS_CTYPE_ENFORCED
1466 bool "Issue a diagnostic and abort()"
1471 config UCLIBC_HAS_WCHAR
1472 bool "Wide Character Support"
1474 Answer Y to enable wide character support. This will make uClibc
1475 much larger. It is also currently required for locale support.
1477 Most people will answer N.
1479 config UCLIBC_HAS_LOCALE
1480 bool "Locale Support"
1481 select UCLIBC_HAS_WCHAR
1482 select UCLIBC_HAS_CTYPE_TABLES
1484 uClibc now has full ANSI/ISO C99 locale support (except for
1485 wcsftime() and collating items in regex). Be aware that enabling
1486 this option will make uClibc much larger.
1488 Enabling UCLIBC_HAS_LOCALE with the default set of supported locales
1489 (169 UTF-8 locales, and 144 locales for other codesets) will enlarge
1490 uClibc by around 300k. You can reduce this size by building your own
1491 custom set of locate data (see extra/locale/LOCALES for details).
1493 uClibc's locale support is still under development. For example,
1494 codesets using shift states are not currently supported. Support is
1495 planned in the next iteration of locale support.
1497 Answer Y to enable locale support. Most people will answer N.
1501 prompt "Locale data"
1502 depends on UCLIBC_HAS_LOCALE
1503 default UCLIBC_BUILD_ALL_LOCALE
1505 config UCLIBC_BUILD_ALL_LOCALE
1507 depends on UCLIBC_HAS_LOCALE
1509 This builds all the locales that are available on your
1512 config UCLIBC_BUILD_MINIMAL_LOCALE
1513 bool "Only selected locales"
1514 depends on UCLIBC_HAS_LOCALE
1516 If you do not need all locales that are available on your
1517 host-box, then set this to 'Y'.
1519 config UCLIBC_PREGENERATED_LOCALE_DATA
1520 bool "Use Pre-generated Locale Data"
1521 depends on UCLIBC_HAS_LOCALE && !TARGET_metag
1523 Use pre-built locale data.
1525 Note that these pregenerated locales are sensitive to your
1526 target architecture (endianess, bitcount).
1528 Saying N here is highly recommended.
1532 config UCLIBC_BUILD_MINIMAL_LOCALES
1533 string "locales to use"
1534 depends on UCLIBC_BUILD_MINIMAL_LOCALE
1537 Space separated list of locales to use.
1544 config UCLIBC_DOWNLOAD_PREGENERATED_LOCALE_DATA
1545 bool "Automagically Download the Pre-generated Locale Data (if necessary)"
1546 depends on UCLIBC_PREGENERATED_LOCALE_DATA
1548 If you would like the build process to use 'wget' to automatically
1549 download the pregenerated locale data, enable this option. Otherwise
1550 you will need to obtain the locale data yourself from:
1551 http://www.uclibc.org/downloads/uClibc-locale-*.tgz
1552 and place the uClibc-locale-*.tgz tarball in the extra/locale/
1555 Note that the use of pregenerated locale data is discouraged.
1557 config UCLIBC_HAS_XLOCALE
1558 bool "Extended Locale Support (experimental/incomplete)"
1559 depends on UCLIBC_HAS_LOCALE
1561 Answer Y to enable extended locale support similar to that provided
1562 by glibc. This is primarily intended to support libstd++
1564 However, it also allows thread-specific locale selection via
1567 Most people will answer N.
1569 config UCLIBC_HAS_HEXADECIMAL_FLOATS
1570 bool "Support hexadecimal float notation"
1571 depends on UCLIBC_HAS_CTYPE_TABLES
1572 depends on UCLIBC_HAS_FLOATS
1574 Answer Y to enable support for hexadecimal float notation in the
1575 (wchar and) char string to floating point conversion functions, as
1576 well as support for the %a and %A conversion specifiers in the
1577 *printf() and *scanf() functions.
1579 Most people will answer N.
1581 config UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1582 bool "Support glibc's \"'\" flag for allowing locale-specific digit grouping"
1583 depends on UCLIBC_HAS_LOCALE
1584 depends on UCLIBC_HAS_FLOATS
1586 Answer Y to enable support for glibc's \"'\" flag for allowing
1587 locale-specific digit grouping in base 10 integer conversions and
1588 appropriate floating point conversions in the *printf() and *scanf()
1591 Most people will answer N.
1593 config UCLIBC_HAS_SCANF_LENIENT_DIGIT_GROUPING
1594 bool "Do not require digit grouping when the \"'\" flag is specified"
1595 depends on UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1598 Answer Y to make digit grouping optional when the \"'\" flag is
1600 This is the standard glibc behavior. If the initial string of digits
1601 exceeds the maximum group number, the input will be treated as a
1602 normal non-grouped number.
1604 Most people will answer N.
1606 config UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
1607 bool "Support glibc's register_printf_function() (glibc-compat)"
1608 depends on !USE_OLD_VFPRINTF
1610 Answer Y to support glibc's register_printf_function() to allow an
1611 application to add its own printf conversion specifiers.
1612 parse_printf_format() is also enabled.
1614 NOTE: Limits the number or registered specifiers to 10.
1615 NOTE: Requires new conversion specifiers to be ASCII
1616 characters (0-0x7f). This is to avoid problems with processing
1617 format strings in locales with different multibyte conversions.
1619 Most people will answer N.
1621 config USE_OLD_VFPRINTF
1622 bool "Use the old vfprintf implementation"
1623 depends on !UCLIBC_HAS_WCHAR
1625 Set to true to use the old vfprintf instead of the new. This is
1626 roughly C89 compliant with some extensions, and is much smaller.
1627 However, it does not support wide chars, positional args, or glibc
1628 custom printf specifiers.
1630 Most people will answer N.
1632 config UCLIBC_PRINTF_SCANF_POSITIONAL_ARGS
1633 int "Maximum number of positional args. Either 0 or >= 9."
1634 depends on !USE_OLD_VFPRINTF
1637 Set the maximum number of positional args supported by the
1638 printf/scanf functions. The Single Unix Specification Version 3
1639 requires a minimum value of 9. Setting this to a value lower than
1640 9 will disable positional arg support and cause the NL_ARGMAX macro
1641 in limits.h to be #undef'd.
1643 WARNING! The workspace to support positional args is currently
1644 allocated on the stack. You probably don't want to set
1645 this to too high a value.
1647 Most people will answer 9.
1650 prompt "Stdio buffer size"
1651 default UCLIBC_HAS_STDIO_BUFSIZ_4096
1653 Please select a value for BUFSIZ. This will be used by the
1654 stdio subsystem as the default buffer size for a file, and
1655 affects fopen(), setvbuf(), etc.
1657 NOTE: Setting this to 'none' will disable buffering completely.
1658 However, BUFSIZ will still be defined in stdio.h as 256 because
1659 many applications use this value.
1661 config UCLIBC_HAS_STDIO_BUFSIZ_NONE
1662 bool "none (WARNING - BUFSIZ will be 256 in stdio.h)"
1663 depends on !UCLIBC_HAS_WCHAR
1665 config UCLIBC_HAS_STDIO_BUFSIZ_256
1666 bool "256 (minimum ANSI/ISO C99 value)"
1668 config UCLIBC_HAS_STDIO_BUFSIZ_512
1671 config UCLIBC_HAS_STDIO_BUFSIZ_1024
1674 config UCLIBC_HAS_STDIO_BUFSIZ_2048
1677 config UCLIBC_HAS_STDIO_BUFSIZ_4096
1680 config UCLIBC_HAS_STDIO_BUFSIZ_8192
1683 # If you add more choices, you will need to update uClibc_stdio.h.
1688 prompt "Stdio builtin buffer size (uClibc-specific)"
1689 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1690 default UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1692 When a FILE is created with fopen(), an attempt is made to allocate
1693 a BUFSIZ buffer for it. If the allocation fails, fopen() will still
1694 succeed but the FILE will be unbuffered.
1696 This option adds a small amount of space to each FILE to act as an
1697 emergency buffer in the event of a buffer allocation failure.
1699 Most people will answer None.
1701 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1704 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_4
1707 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8
1710 # If you add more choices, you will need to update uClibc_stdio.h.
1714 config UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT
1715 bool "Attempt to shutdown stdio subsystem when abort() is called."
1717 ANSI/ISO C99 requires abort() to be asyn-signal-safe. So there was
1718 a behavioral change made in SUSv3. Previously, abort() was required
1719 to have the affect of fclose() on all open streams. The wording has
1720 been changed to "may" from "shall".
1722 Most people will answer N.
1724 config UCLIBC_HAS_STDIO_GETC_MACRO
1725 bool "Provide a macro version of getc()"
1726 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1729 Provide a macro version of getc().
1731 Most people will answer Y.
1733 config UCLIBC_HAS_STDIO_PUTC_MACRO
1734 bool "Provide a macro version of putc()"
1735 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1738 Provide a macro version of putc().
1740 Most people will answer Y.
1742 config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION
1743 bool "Support auto-r/w transition"
1746 Answer Y to enable the stdio subsystem to automaticly transition
1747 between reading and writing. This relaxes the ANSI/ISO C99
1750 When a file is opened with update mode ('+' as the second or third
1751 character in the list of mode argument values), both input and output
1752 may be performed on the associated stream. However, output shall not
1753 be directly followed by input without an intervening call to the
1754 fflush function or to a file positioning function (fseek, fsetpos,
1755 or rewind), and input shall not be directly followed by output without
1756 an intervening call to a file positioning function, unless the input
1757 operation encounters endÂofÂfile.
1759 Most people will answer Y.
1761 config UCLIBC_HAS_FOPEN_LARGEFILE_MODE
1762 bool "Support an fopen() 'F' flag for large file mode (uClibc-specific)"
1763 depends on UCLIBC_HAS_LFS
1765 Answer Y to enable a uClibc-specific extension to allow passing an
1766 additional 'F' flag in the mode string for fopen() to specify that
1767 the file should be open()ed with the O_LARGEFILE flag set.
1769 Most people will answer N.
1771 config UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
1772 bool "Support an fopen() 'x' flag for exclusive mode (glibc-compat)"
1774 Answer Y to support a glibc extension to allow passing
1775 additional 'x' flag in the mode string for fopen() to specify that
1776 the file should be open()ed with the O_EXCL flag set.
1778 Most people will answer N.
1780 config UCLIBC_HAS_FOPEN_CLOSEEXEC_MODE
1781 bool "Support an fopen() 'e' flag for close-on-exec mode (glibc-compat)"
1783 Answer Y to support a glibc extension to allow passing
1784 additional 'e' flag in the mode string for fopen() to specify that
1785 the file should be open()ed with the O_CLOEXEC flag set.
1787 Most people will answer N.
1789 config UCLIBC_HAS_GLIBC_CUSTOM_STREAMS
1790 bool "Support fmemopen(), open_memstream(), and fopencookie() (glibc-compat)"
1792 Answer Y to support the glibc 'custom stream' extension functions
1793 fmemopen(), open_memstream(), and fopencookie().
1795 NOTE: There are some minor differences regarding seeking behavior.
1797 Most people will answer N.
1799 config UCLIBC_HAS_PRINTF_M_SPEC
1800 bool "Support the '%m' specifier in printf format strings (glibc-compat)"
1802 Answer Y to support a glibc extension to interpret '%m' in printf
1803 format strings as an instruction to output the error message string
1804 (as generated by strerror) corresponding to the current value of
1807 Most people will answer N.
1809 config UCLIBC_HAS_ERRNO_MESSAGES
1810 bool "Include the errno message text in the library"
1813 Answer Y if you want to include the errno message text in the
1814 library. This adds about 3K to the library, but enables strerror()
1815 to generate text other than 'Unknown error <number>'.
1817 Most people will answer Y.
1819 config UCLIBC_HAS_SYS_ERRLIST
1820 bool "Support sys_errlist[] (obsolete-compat)"
1821 depends on UCLIBC_HAS_ERRNO_MESSAGES
1823 Answer Y if you want to support the obsolete sys_errlist[].
1824 This adds about 0.5k to the library, except for the mips
1825 arch where it adds over 4K.
1827 WARNING! In the future, support for sys_errlist[] may be unavailable
1828 in at least some configurations. In fact, it may be removed
1831 Most people will answer N.
1833 Application writers: use the strerror(3) function.
1835 config UCLIBC_HAS_SIGNUM_MESSAGES
1836 bool "Include the signum message text in the library"
1839 Answer Y if you want to include the signum message text in the
1840 library. This adds about 0.5K to the library, but enables strsignal()
1841 to generate text other than 'Unknown signal <number>'.
1843 Most people will answer Y.
1845 config UCLIBC_HAS_SYS_SIGLIST
1846 bool "Support sys_siglist[] (bsd-compat)"
1847 depends on UCLIBC_HAS_SIGNUM_MESSAGES
1849 Answer Y if you want to support sys_siglist[].
1851 WARNING! In the future, support for sys_siglist[] may be unavailable
1852 in at least some configurations. In fact, it may be removed
1855 Most people will answer N.
1857 config UCLIBC_HAS_GETTEXT_AWARENESS
1858 bool "Include gettext awareness"
1859 depends on UCLIBC_HAS_LOCALE && UCLIBC_MJN3_ONLY
1861 NOTE!!! Not yet integrated with strerror and strsignal. NOTE!!!
1863 Answer Y if you want to include weak stub gettext support and
1864 make the *strerror*() and strsignal() functions gettext-aware.
1866 Currently, to get functional gettext functionality you will need
1869 Most people will answer N.
1871 config UCLIBC_HAS_GNU_GETOPT
1872 bool "Support gnu getopt"
1875 Answer Y if you want to include full gnu getopt() instead of a
1876 (much smaller) SUSv3 compatible getopt().
1878 Most people will answer Y.
1880 config UCLIBC_HAS_STDIO_FUTEXES
1881 bool "Use futexes for multithreaded I/O locking"
1882 depends on UCLIBC_HAS_THREADS_NATIVE
1884 If you want to compile uClibc to use futexes for low-level
1885 I/O locking, answer Y. Otherwise, answer N.
1887 config UCLIBC_HAS_GETOPT_LONG
1888 bool "Support getopt_long/getopt_long_only"
1889 depends on !UCLIBC_HAS_GNU_GETOPT
1892 Answer Y if you want to include getopt_long[_only() used by many
1895 Most people will answer Y.
1897 config UCLIBC_HAS_GNU_GETSUBOPT
1898 bool "Support glibc getsubopt"
1901 Answer Y if you want to include glibc getsubopt() instead of a
1902 smaller SUSv3 compatible getsubopt().
1904 Most people will answer Y.
1910 config UCLIBC_HAS_REGEX
1911 bool "Regular Expression Support"
1914 POSIX regular expression code is really big -- 53k all by itself.
1915 If you don't use regular expressions, turn this off and save space.
1916 Of course, if you only statically link, leave this on, since it will
1917 only be included in your apps if you use regular expressions.
1919 config UCLIBC_HAS_REGEX_OLD
1920 bool "Use the older (stable) regular expression code"
1921 depends on UCLIBC_HAS_REGEX
1924 There are two versions of regex. The older (stable) version has
1925 been in uClibc for quite a long time but hasn't seen too many
1926 updates. It also has some known issues when dealing with uncommon
1927 corner cases and multibyte/unicode strings. However, it is quite
1928 a bit smaller than the newer version.
1930 If the older version has worked for you and you don't need unicode
1931 support, then stick with the old version (and say Y here).
1932 Otherwise, you should use the new version (and say N here).
1934 config UCLIBC_HAS_FNMATCH
1935 bool "fnmatch Support"
1940 config UCLIBC_HAS_FNMATCH_OLD
1941 bool "Use the older (stable) fnmatch code"
1942 depends on UCLIBC_HAS_FNMATCH
1945 There are two versions of fnmatch. The older (stable) version has
1946 been in uClibc for quite a long time but hasn't seen too many
1947 updates. It also has some known issues when dealing with uncommon
1948 corner cases and multibyte/unicode strings. However, it is quite
1949 a bit smaller than the newer version.
1951 If the older version has worked for you and you don't need unicode
1952 support, then stick with the old version (and say Y here).
1953 Otherwise, you should use the new version (and say N here).
1955 config UCLIBC_HAS_WORDEXP
1956 bool "Support the wordexp() interface"
1957 depends on UCLIBC_HAS_GLOB
1959 The SuSv3 wordexp() interface performs word expansions per the Shell
1960 and Utilities volume of IEEE Std 1003.1-2001, Section 2.6. It is
1961 intended for use by applications that want to implement all of the
1962 standard Bourne shell expansions on input data.
1964 This interface is rarely used, and very large. Unless you have a
1965 pressing need for wordexp(), you should probably answer N.
1967 config UCLIBC_HAS_NFTW
1968 bool "Support the nftw() interface"
1970 The SuSv3 nftw() interface is used to recursively descend
1971 directory paths while repeatedly calling a function.
1973 This interface is rarely used, and adds around 4.5k. Unless you have
1974 a pressing need for nftw(), you should probably answer N.
1976 config UCLIBC_HAS_FTW
1977 bool "Support the ftw() interface (SUSv4-obsolete)"
1978 depends on UCLIBC_SUSV4_LEGACY
1980 The SuSv3 ftw() interface is used to recursively descend
1981 directory paths while repeatedly calling a function.
1983 This interface is rarely used, and adds around 4.5k. Unless you have
1984 a pressing need for ftw(), you should probably answer N.
1986 config UCLIBC_HAS_FTS
1987 bool "Support the fts() interface (bsd-compat)"
1989 The fts functions are provided for traversing UNIX file hierarchies.
1991 This interface is currently used by the elfutils and adds
1993 You should port your application to use the POSIX nftw()
1996 Unless you need to build/use elfutils, you should prolly answer N.
1998 config UCLIBC_HAS_GLOB
1999 bool "Support the glob() interface"
2000 depends on UCLIBC_HAS_FNMATCH
2004 The glob interface is somewhat large (weighing in at about 2,5k). It
2005 is used fairly often, but is an option since people wanting to go for
2006 absolute minimum size may wish to omit it.
2008 Most people will answer Y.
2010 config UCLIBC_HAS_GNU_GLOB
2011 bool "Support gnu glob() interface"
2012 depends on UCLIBC_HAS_GLOB
2014 The gnu glob interface is somewhat larger (weighing in at about 4,2k)
2015 than it's SuSv3 counterpart (and is out of date). It is an old copy
2016 from glibc and does not support all the GNU specific options.
2018 Answer Y if you want to include full gnu glob() instead of the smaller
2019 SUSv3 compatible glob().
2021 Most people will answer N.
2023 config UCLIBC_HAS_UTMPX
2024 bool "utmpx based support for tracking login/logouts to/from the system"
2026 Answer y to enable support for accessing user accounting database.
2027 It can be used to track all login/logout to the system.
2029 If unsure, just answer N.
2036 menu "Library Installation Options"
2038 config RUNTIME_PREFIX
2039 string "uClibc runtime library directory"
2040 default "/usr/$(TARGET_ARCH)-linux-uclibc/"
2042 RUNTIME_PREFIX is the directory into which the uClibc runtime
2043 libraries will be installed. The result will look something
2046 lib/ <contains all runtime libraries>
2047 usr/bin/ldd <the ldd utility program>
2048 sbin/ldconfig <the ldconfig utility program>
2049 This value is used by the 'make install' Makefile target. Since this
2050 directory is compiled into the shared library loader, you will need to
2051 recompile uClibc if you change this value...
2053 For a typical target system this should be set to "/", such that
2054 'make install' will install /lib/libuClibc-<VERSION>.so
2057 string "uClibc development environment directory"
2058 default "/usr/$(TARGET_ARCH)-linux-uclibc/usr/"
2060 DEVEL_PREFIX is the directory into which the uClibc development
2061 environment will be installed. The result will look something
2064 lib/ <contains static libs>
2065 include/ <Where all the header files go>
2066 This value is used by the 'make install' Makefile target when
2067 installing a uClibc development environment.
2069 For a typical target system this should be set to "/usr", such that
2070 'make install' will install /usr/include/<header files>.
2073 string "library path component"
2076 Path component where libraries reside.
2078 For a typical target system this should be set to "lib", such that
2079 'make install' will install libraries to "/lib" and "/usr/lib"
2081 DEVEL_PREFIX/MULTILIB_DIR
2082 RUNTIME_PREFIX/MULTILIB_DIR
2084 Other settings may include "lib32" or "lib64".
2086 config HARDWIRED_ABSPATH
2087 bool "Hardwire absolute paths into linker scripts"
2090 This prepends absolute paths to the libraries mentioned in linker
2091 scripts such as libc.so.
2093 This is a build time optimization. It has no impact on dynamic
2094 linking at runtime, which doesn't use linker scripts.
2096 You must disable this to use uClibc with old non-sysroot toolchains,
2097 such as the prebuilt binary cross compilers at:
2098 http://uclibc.org/downloads/binaries
2100 The amount of time saved by this optimization is actually too small to
2101 measure. The linker just had to search the library path to find the
2102 linker script, so the dentries are cache hot if it has to search the
2103 same path again. But it's what glibc does, so we do it too.
2108 menu "Security options"
2110 config UCLIBC_BUILD_PIE
2111 bool "Build utilities as ET_DYN/PIE executables"
2112 depends on HAVE_SHARED
2113 depends on TARGET_arm || TARGET_frv || TARGET_i386 || TARGET_mips || TARGET_powerpc
2114 select FORCE_SHAREABLE_TEXT_SEGMENTS
2116 If you answer Y here, ldd and iconv are built as ET_DYN/PIE
2119 It requires gcc-3.4 and binutils-2.15 (for arm 2.16) or later.
2120 More about ET_DYN/PIE binaries on <http://pax.grsecurity.net/> .
2122 WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so
2123 all libraries have to be built with -fPIC or -fpic, and all
2124 assembler functions must be written as position independent
2127 config UCLIBC_HAS_ARC4RANDOM
2128 bool "Include the arc4random() function"
2130 Answer Y to support the OpenBSD-like arc4random() function. This
2131 function picks a random number between 0 and N, and will always return
2132 something even if the random driver is dead. If urandom fails then
2133 gettimeofday(2) will be used as the random seed. This function is
2134 designed to be more dependable than invoking /dev/urandom directly.
2135 OpenSSL and OpenNTPD currently support this function.
2137 Most people will answer N.
2139 config ARC4RANDOM_USES_NODEV
2140 bool "Do not use /dev/urandom with arc4random()"
2141 depends on UCLIBC_HAS_ARC4RANDOM
2143 Answer Y to use gettimeofday(2) and getpid(2) exclusively for
2144 arc4random(). This is not a bad idea for a diskless system, but
2145 it uses a lot of syscalls to stir each array element.
2147 Most people will answer N.
2152 config UCLIBC_HAS_SSP
2153 bool "Support for GCC stack smashing protector"
2154 depends on !HAVE_NO_SSP
2156 Add code to support GCC's -fstack-protector[-all] option to uClibc.
2157 This requires GCC 4.1 or newer. GCC does not have to provide libssp,
2158 the needed functions are added to ldso/libc instead.
2160 GCC's stack protector is a reimplementation of IBM's propolice.
2161 See http://www.trl.ibm.com/projects/security/ssp/ and
2162 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
2165 Note that NOEXECSTACK on a kernel with address space randomization
2166 is generally sufficient to prevent most buffer overflow exploits
2167 without increasing code size. This option essentially adds debugging
2170 Most people will answer N.
2172 config UCLIBC_HAS_SSP_COMPAT
2173 bool "Support for gcc-3.x propolice smashing stack protector"
2174 depends on UCLIBC_HAS_SSP
2176 Add gcc-3.x propolice smashing stack protector to the library.
2178 This requires a patched version of GCC, supporting the
2179 -fstack-protector[-all] options, with the __guard and
2180 __stack_smash_handler functions removed from libgcc.
2181 These functions are added to ldso/libc instead.
2183 More information at:
2184 <http://www.research.ibm.com/trl/projects/security/ssp/>
2186 Most people will answer N.
2188 config SSP_QUICK_CANARY
2189 bool "Use simple guard values without accessing /dev/urandom"
2190 depends on UCLIBC_HAS_SSP
2192 Use gettimeofday(2) to define the __guard without accessing
2194 WARNING: This makes smashing stack protector vulnerable to timing
2196 Most people will answer N.
2199 prompt "Propolice protection blocking signal"
2200 depends on UCLIBC_HAS_SSP
2202 default PROPOLICE_BLOCK_SEGV
2204 "abort" use SIGABRT to block offending programs.
2205 This is the default implementation.
2207 "segfault" use SIGSEGV to block offending programs.
2208 Use this for debugging.
2210 If unsure, answer "abort".
2212 config PROPOLICE_BLOCK_ABRT
2215 config PROPOLICE_BLOCK_SEGV
2220 config UCLIBC_BUILD_SSP
2221 bool "Build uClibc with -fstack-protector"
2222 depends on UCLIBC_HAS_SSP
2224 Build all uClibc libraries and executables with -fstack-protector,
2225 adding extra stack overflow checking to most uClibc functions.
2227 config UCLIBC_BUILD_RELRO
2228 bool "Build uClibc with linker option -z RELRO"
2229 depends on HAVE_SHARED
2232 Build all libraries and executables with "ld -z relro".
2234 This tells the linker to mark chunks of an executable or shared
2235 library read-only after applying dynamic relocations. (This comes
2236 up when a global const variable is initialized to the address of a
2237 function or the value of another global variable.)
2239 This is a fairly obscure option the ld man page doesn't even bother
2240 to document properly. It's a security paranoia issue that's more
2241 likely to consume memory (by allocating an extra page) rather than
2244 This is explained in more depth at
2245 http://www.airs.com/blog/archives/189
2247 Nobody is likely to care whether you say Y or N here.
2249 config UCLIBC_BUILD_NOW
2250 bool "Build uClibc with linker option -z NOW"
2251 depends on HAVE_SHARED
2253 Build all libraries and executables with "ld -z now".
2255 This tells the linker to resolve all symbols when the library is
2256 first loaded, rather than when each function is first called. This
2257 increases start-up latency by a few microseconds and may do
2258 unnecessary work (resolving symbols that are never used), but the
2259 realtime people like it for making microbenchmark timings slightly
2260 more predictable and in some cases it can be slightly faster due to
2261 CPU cache behavior (not having to fault the linker back in to do
2262 lazy symbol resolution).
2264 Most people can't tell the difference between selecting Y or N here.
2266 config UCLIBC_BUILD_NOEXECSTACK
2267 bool "Build uClibc with noexecstack marking"
2270 Mark all assembler files as noexecstack, which will mark uClibc
2271 as not requiring an executable stack. (This doesn't prevent other
2272 files you link against from claiming to need an executable stack, it
2273 just won't cause uClibc to request it unnecessarily.)
2275 This is a security thing to make buffer overflows harder to exploit.
2276 By itself, it's kind of useless, as Linus Torvalds explained in 1998:
2277 http://old.lwn.net/1998/0806/a/linus-noexec.html
2279 It only actually provides any security when combined with address
2280 space randomization, explained here: http://lwn.net/Articles/121845/
2282 Address space randomization is on by default in current linux
2283 kernels (although it can be disabled using the option
2286 You should probably say Y.
2290 menu "Development/debugging options"
2292 config CROSS_COMPILER_PREFIX
2293 string "Cross-compiling toolchain prefix"
2296 The prefix used to execute your cross-compiling toolchain. For
2297 example, if you run 'arm-linux-uclibc-gcc' to compile something,
2298 then enter 'arm-linux-uclibc-' here.
2300 config UCLIBC_EXTRA_CFLAGS
2301 string "Extra CFLAGS"
2304 Add any additional CFLAGS to be used to build uClibc.
2307 bool "Enable debugging symbols"
2308 select EXTRA_WARNINGS
2310 Say Y here if you wish to compile uClibc with debugging symbols.
2311 This will allow you to use a debugger to examine uClibc internals
2312 while applications are running. This increases the size of the
2313 library considerably and should only be used when doing development.
2314 If you are doing development and want to debug uClibc, answer Y.
2316 Otherwise, answer N.
2319 bool "Build pthread with debugging output"
2320 depends on UCLIBC_HAS_THREADS && LINUXTHREADS_OLD
2322 Enable debug output in libpthread. This is only useful when doing
2323 development in libpthread itself.
2325 Otherwise, answer N.
2328 bool "Strip libraries and executables"
2332 Say Y here if you do wish to strip all uClibc libraries and
2333 executables. No stripping increases the size of the binaries
2334 considerably, but makes it possible to debug uClibc libraries.
2335 Most people will answer Y.
2338 bool "Build with run-time assertion testing"
2340 Say Y here to include runtime assertion tests.
2341 This enables runtime assertion testing in some code, which can
2342 increase the size of the library and incur runtime overhead.
2343 If you say N, then this testing will be disabled.
2345 config SUPPORT_LD_DEBUG
2346 bool "Build the shared library loader with debugging support"
2347 depends on HAVE_SHARED
2349 Answer Y here to enable all the extra code needed to debug the uClibc
2350 native shared library loader. The level of debugging noise that is
2351 generated depends on the LD_DEBUG environment variable... Just set
2352 LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
2353 debug your application. Diagnostic messages will then be printed to
2356 For now these debugging tokens are available:
2357 detail provide more information for some options
2358 move display copy processing
2359 symbols display symbol table processing
2360 reloc display relocation processing; detail shows the
2362 nofixups never fixes up jump relocations
2363 bindings displays the resolve processing (function calls);
2364 detail shows the relocation patch
2365 all Enable everything!
2367 The additional environment variable:
2368 LD_DEBUG_OUTPUT=file
2369 redirects the diagnostics to an output file created using
2370 the specified name and the process id as a suffix.
2372 An excellent start is simply:
2373 $ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
2374 or to log everything to a file named 'logfile', try this
2375 $ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
2377 If you are doing development and want to debug uClibc's shared library
2378 loader, answer Y. Mere mortals answer N.
2380 config SUPPORT_LD_DEBUG_EARLY
2381 bool "Build the shared library loader with early debugging support"
2382 depends on HAVE_SHARED
2384 Answer Y here to if you find the uClibc shared library loader is
2385 crashing or otherwise not working very early on. This is typical
2386 only when starting a new port when you haven't figured out how to
2387 properly get the values for argc, argv, environ, etc. This method
2388 allows a degree of visibility into the very early shared library
2389 loader initialization process. If you are doing development and want
2390 to debug the uClibc shared library loader early initialization,
2391 answer Y. Mere mortals answer N.
2393 config UCLIBC_MALLOC_DEBUGGING
2394 bool "Build malloc with debugging support"
2395 depends on MALLOC || MALLOC_STANDARD
2398 Answer Y here to compile extra debugging support code into malloc.
2399 Malloc debugging output may then be enabled at runtime using the
2400 MALLOC_DEBUG environment variable.
2402 The value of MALLOC_DEBUG should be an integer, which is interpreted
2403 as a bitmask with the following bits:
2404 1 - do extra consistency checking
2405 2 - output messages for malloc/free calls and OS
2407 4 - output messages for the `MMB' layer
2408 8 - output messages for internal malloc heap manipulation
2411 Because this increases the size of malloc appreciably (due to strings
2412 etc), you should say N unless you need to debug a malloc problem.
2414 config UCLIBC_HAS_BACKTRACE
2415 bool "Add support for application self-debugging"
2416 depends on HAVE_SHARED
2418 Answer Y here to compile support for application self-debugging, by adding
2419 a new shared object "libubacktrace.so" that provides the following new
2421 backtrace, backtrace_symbols, backtrace_symbols_fd
2423 The backtrace functionality is currently supported on SH platform, and it
2424 based on dwarf2 informations to properly work, so any application that
2425 want to use backtrace needs to be built with -fexceptions flag.
2427 The symbol names may be unavailable without the use of special linker
2428 options. For systems using the GNU linker, it is necessary to use the
2429 -rdynamic linker option too. Note that names of "static" functions are not
2430 exposed, and won't be available in the backtrace.
2433 string "Compiler Warnings"
2436 Set this to the set of compiler warnings you wish to see while compiling.
2438 config EXTRA_WARNINGS
2439 bool "Enable extra annoying warnings"
2441 If you wish to build with extra warnings enabled, say Y here.
2444 bool "Compile all sources at once into an object"
2446 Set this to compile all sources at once into an object (IMA).
2447 This mode of compilation uses alot of memory but may produce
2450 Note that you need a very recent GCC for this to work, like
2451 gcc >= 4.3 plus eventually some patches.
2453 If unsure, keep the default of N.
2455 config UCLIBC_MJN3_ONLY
2456 bool "Manuel's hidden warnings"
2458 Answer Y here to see all Manuel's personal notes, warnings, and todos.
2460 Most people will answer N.
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