1 .\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>.
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23 .TH LSEEK64 3 2004-12-11 "Linux" "Linux Programmer's Manual"
25 lseek64 \- reposition 64-bit read/write file offset
27 .BR "#define _LARGEFILE64_SOURCE" " /* See feature_test_macros(7) */"
29 .B #include <sys/types.h>
31 .B #include <unistd.h>
33 .BI "off64_t lseek64(int " fd ", off64_t " offset ", int " whence );
37 family of functions reposition the offset of the open file associated
38 with the file descriptor
42 bytes relative to the start, current position, or end of the file,
52 For more details, return value, and errors, see
55 Four interfaces are available:
59 and the raw system call
66 .BI "off_t lseek(int " fd ", off_t " offset ", int " whence );
73 This is a 32-bit signed type on 32-bit architectures, unless one
78 #define _FILE_OFFSET_BITS 64
82 in which case it is a 64-bit signed type.
88 .BI "off64_t lseek64(int " fd ", off64_t " offset ", int " whence );
94 uses a 64-bit type even when
97 Its prototype (and the type
99 is available only when one compiles with
103 #define _LARGEFILE64_SOURCE
109 .\" in glibc 2.0.94, not in 2.0.6
110 is available since glibc 2.1, and is defined to be an alias for
117 .BI "loff_t llseek(int " fd ", loff_t " offset ", int " whence );
123 is a 64-bit signed type.
126 .\" in libc 5.0.9, not in 4.7.6
127 is available in libc5 and glibc and works without special defines.
128 Its prototype was given in
130 with libc5, but glibc does not provide a prototype.
131 This is bad, since a prototype is needed.
133 the above prototype, or something equivalent, to their own source.
134 When users complained about data loss caused by a miscompilation of
136 glibc 2.1.3 added the link-time warning
139 "the \`llseek\' function may be dangerous; use \`lseek64\' instead."
142 This makes this function unusable if one desires a warning-free
145 All the above functions are implemented in terms of this system call.
150 .BI "int _llseek(int " fd ", off_t " offset_hi ", off_t " offset_lo ,
151 .BI " loff_t *" result ", int " whence );
155 For more details, see