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The following macros check for operating system services or capabilities.
Try to locate the X Window System include files and libraries. If the user gave the command line options --x-includes=dir and --x-libraries=dir, use those directories.
If either or both were not given, get the missing values by running
xmkmf (or an executable pointed to by the XMKMF
environment variable) on a trivial Imakefile and examining the
makefile that it produces. Setting XMKMF to ‘false’
disables this method.
If this method fails to find the X Window System, configure
looks for the files in several directories where they often reside.
If either method is successful, set the shell variables
x_includes and x_libraries to their locations, unless they
are in directories the compiler searches by default.
If both methods fail, or the user gave the command line option
--without-x, set the shell variable no_x to ‘yes’;
otherwise set it to the empty string.
An enhanced version of AC_PATH_X. It adds the C compiler flags
that X needs to output variable X_CFLAGS, and the X linker flags
to X_LIBS. Define X_DISPLAY_MISSING if X is not
available.
This macro also checks for special libraries that some systems need in
order to compile X programs. It adds any that the system needs to
output variable X_EXTRA_LIBS. And it checks for special X11R6
libraries that need to be linked with before -lX11, and adds
any found to the output variable X_PRE_LIBS.
Check whether the system supports starting scripts with a line of the
form ‘#!/bin/sh’ to select the interpreter to use for the script.
After running this macro, shell code in configure.ac can check
the shell variable interpval; it is set to ‘yes’
if the system supports ‘#!’, ‘no’ if not.
Arrange for 64-bit file offsets, known as
large-file support. On some hosts, one must use special compiler
options to build programs that can access large files. Append any such
options to the output variable CC. Define
_FILE_OFFSET_BITS and _LARGE_FILES if necessary.
Large-file support can be disabled by configuring with the --disable-largefile option.
If you use this macro, check that your program works even when
off_t is wider than long int, since this is common when
large-file support is enabled. For example, it is not correct to print
an arbitrary off_t value X with printf ("%ld",
(long int) X). Also, when using this macro in concert with
AC_CONFIG_HEADERS, be sure that config.h is included
before any system header.
The LFS introduced the fseeko and ftello functions to
replace their C counterparts fseek and ftell that do not
use off_t. Take care to use AC_FUNC_FSEEKO to make their
prototypes available when using them and large-file support is
enabled.
If the system supports file names longer than 14 characters, define
HAVE_LONG_FILE_NAMES.
Check to see if the Posix termios headers and functions are available on the
system. If so, set the shell variable ac_cv_sys_posix_termios to
‘yes’. If not, set the variable to ‘no’.
Next: C and Posix Variants, Previous: Compilers and Preprocessors, Up: Existing Tests [Contents][Index]