ax_sys_largefile_sensitive (Autoconf Archive)

ax_sys_largefile_sensitive

Synopsis

AX_SYS_LARGEFILE_SENSITIVE

Description

Check 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 needed to make the code use 64bit off_t - in many setups this will also make the code use 64bit off_t immediately.

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

Source Code

Download the latest version of ax_sys_largefile_sensitive.m4 or browse the macro’s revision history.

License

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without any warranty.