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AC_SYS_LARGEFILE_SENSITIVE
1.2 (2003/05/13) 0.5.57 : System Headers
Guido Draheim <guidod@gmx.de>
checker whether the current system is sensitive to -Ddefines making off_t having different types/sizes. Automatically define a config.h symbol LARGEFILE_SENSITIVE if that is the case, otherwise leave everything as is.
This macro builds on top of AC_SYS_LARGEFILE to detect whether special options are neede to make the code use 64bit off_t - in many setups this will also make the code use 64bit off_t immediatly.
The common use of a LARGEFILE_SENSITIVE config.h-define is to rename exported functions, usually adding a 64 to the original function name. Such renamings are only needed on systems being both (a) 32bit off_t by default and (b) implementing large.file extensions (as for unix98).
a renaming section could look like this:
#if defined LARGEFILE_SENSITIVE && _FILE_OFFSET_BITS+0 == 64
#define zzip_open zzip_open64
#define zzip_seek zzip_seek64
#endif
for libraries, it is best to take advantage of the prefix-config.h macro, otherwise you want to export a renamed LARGEFILE_SENSITIVE in an installed header file. -> see AX_PREFIX_CONFIG_H
AC_DEFUN([AC_SYS_LARGEFILE_SENSITIVE],[dnl AC_REQUIRE([AC_SYS_LARGEFILE])dnl # we know about some internals of ac_sys_largefile here... AC_MSG_CHECKING(whether system differentiates 64bit off_t by defines) ac_cv_sys_largefile_sensitive="no" if test ".$ac_cv_sys_file_offset_bits$ac_cv_sys_large_files" != ".nono" then ac_cv_sys_largefile_sensitive="yes" AC_DEFINE(LARGEFILE_SENSITIVE, 1, [whether the system defaults to 32bit off_t but can do 64bit when requested]) fi AC_MSG_RESULT([$ac_cv_sys_largefile_sensitive]) ])