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generated...
2007-08-05

(C) 2007 guidod
Download the M4 Source.

ac_sys_largefile_sensitive

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Synopsis
AC_SYS_LARGEFILE_SENSITIVE
, 
Version

2006-10-13

Author

Guido U. Draheim <guidod@gmx.de>

License

GPLWithACException
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation. As a special exception, the respective Autoconf Macro's copyright owner gives unlimited permission to copy, distribute and modify the configure scripts that are the output of Autoconf when processing the Macro. You need not follow the terms of the GNU General Public License when using or distributing such scripts

Category

cryp.to ac-archive's Miscellaneous (released)

Documentation

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

M4 Source Code
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])
])