Improve usage notes in stdlib.h, for mkstemp() function.

[mingw/mingw-org-wsl.git] / mingwrt / include / stdlib.h

diff --git a/mingwrt/include/stdlib.h b/mingwrt/include/stdlib.h
index 01fb7a8..cc705b5 100644 (file)
--- a/mingwrt/include/stdlib.h
+++ b/mingwrt/include/stdlib.h
@@ -556,9 +556,76 @@ wchar_t* __cdecl __MINGW_NOTHROW ulltow (unsigned long long _n, wchar_t * _w, in
 #endif /* __MSVCRT__ */
 #endif /* !__NO_ISOCEXT */
 
+/* POSIX/BSD extensions in libmingwex.a; these should be exposed only on
+ * the basis of appropriate POSIX or BSD specific feature tests...
+ *
+ * mkstemp(3) function support; added per feature request #2003.
+ * POSIX wants _XOPEN_SOURCE >= 500, (implying _POSIX_C_SOURCE >= 200112L).
+ */
+#if _POSIX_C_SOURCE >= 200112L
+
+int __cdecl __MINGW_NOTHROW mkstemp( char * );
+int __cdecl __MINGW_NOTHROW __mingw_mkstemp( int, char * );
+
+/* On POSIX platforms, programmers may adopt an idiom such as:
+ *
+ *   if( mkstemp( template ) >= 0 )
+ *   { unlink( template );
+ *     . . .
+ *   }
+ *
+ * to ensure that a temporary file does NOT persist after it is
+ * closed; MS-Windows does not allow such use of unlink(2), while
+ * the file remains open.  Thus, MS-Windows programmers must take
+ * extra care, to close and unlink temporary files AFTER use, if
+ * similar behaviour is desired.
+ *
+ * To mitigate this MS-Windows limitation, we provide support for
+ * an alternative, MinGW specific idiom:
+ *
+ *   #include <fcntl.h>
+ *
+ *   _MKSTEMP_SETMODE( _O_TEMPORARY );
+ *   if( mkstemp( template ) >= 0 )
+ *   {
+ *     . . .
+ *   }
+ *
+ * to achieve a similar effect to that of the above POSIX idiom; the
+ * following macros are a MinGW specific extension, to facilite such
+ * use of _O_TEMPORARY, (in addition to the POSIX required attributes),
+ * when creating the temporary file.  Note that they require fcntl.h,
+ * which stdlib.h should NOT automatically include; we leave the onus
+ * on the user to explicitly include it, if using _MKSTEMP_SETMODE.
+ */
+#define _MKSTEMP_INVOKE       0
+#define _MKSTEMP_DEFAULT     _O_CREAT | _O_EXCL | _O_RDWR
+#define _MKSTEMP_SETMODE(M) __mingw_mkstemp( _MKSTEMP_DEFAULT | (M), NULL )
 
+#ifndef _NO_OLDNAMES
+#define MKSTEMP_SETMODE(M)  __mingw_mkstemp( _MKSTEMP_DEFAULT | (M), NULL )
 #endif
 
+__CRT_ALIAS __LIBIMPL__(( FUNCTION = mkstemp ))
+int __cdecl __MINGW_NOTHROW mkstemp( char *__filename_template )
+{ return __mingw_mkstemp( _MKSTEMP_INVOKE, __filename_template ); }
+
+#endif /* _POSIX_C_SOURCE >= 200112L (for mkstemp()) */
+
+/* mkdtemp(3) function support: added as adjunct to feature request #2003.
+ * POSIX wants _XOPEN_SOURCE >= 700, (implying _POSIX_C_SOURCE >= 200809L).
+ */
+#if _POSIX_C_SOURCE >= 200809L
+
+char * __cdecl __MINGW_NOTHROW mkdtemp( char * );
+char * __cdecl __MINGW_NOTHROW __mingw_mkdtemp( char * );
+
+__CRT_ALIAS __JMPSTUB__(( FUNCTION = mkdtemp ))
+char * __cdecl __MINGW_NOTHROW mkdtemp( char *__dirname_template )
+{ return __mingw_mkdtemp( __dirname_template ); }
+
+#endif /* _POSIX_C_SOURCE >= 200809L (for mkdtemp()) */
+
 _END_C_DECLS
 
 #endif /* Not RC_INVOKED */