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# readlink.m4 serial 16
dnl Copyright (C) 2003, 2007, 2009-2020 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_READLINK],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_FUNCS_ONCE([readlink])
if test $ac_cv_func_readlink = no; then
HAVE_READLINK=0
else
AC_CACHE_CHECK([whether readlink signature is correct],
[gl_cv_decl_readlink_works],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
/* Cause compilation failure if original declaration has wrong type. */
ssize_t readlink (const char *, char *, size_t);]])],
[gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])])
dnl Solaris 9 ignores trailing slash.
dnl FreeBSD 7.2 dereferences only one level of links with trailing slash.
AC_CACHE_CHECK([whether readlink handles trailing slash correctly],
[gl_cv_func_readlink_trailing_slash],
[# We have readlink, so assume ln -s works.
ln -s conftest.no-such conftest.link
ln -s conftest.link conftest.lnk2
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
]], [[char buf[20];
return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
[gl_cv_func_readlink_trailing_slash=yes],
[gl_cv_func_readlink_trailing_slash=no],
[case "$host_os" in
# Guess yes on Linux or glibc systems.
linux-* | linux | *-gnu* | gnu*)
gl_cv_func_readlink_trailing_slash="guessing yes" ;;
# Guess no on AIX or HP-UX.
aix* | hpux*)
gl_cv_func_readlink_trailing_slash="guessing no" ;;
# If we don't know, obey --enable-cross-guesses.
*)
gl_cv_func_readlink_trailing_slash="$gl_cross_guess_normal" ;;
esac
])
rm -f conftest.link conftest.lnk2])
case "$gl_cv_func_readlink_trailing_slash" in
*yes)
if test "$gl_cv_decl_readlink_works" != yes; then
REPLACE_READLINK=1
fi
;;
*)
AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink
fails to recognize a trailing slash.])
REPLACE_READLINK=1
;;
esac
AC_CACHE_CHECK([whether readlink truncates results correctly],
[gl_cv_func_readlink_truncate],
[# We have readlink, so assume ln -s works.
ln -s ab conftest.link
AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <unistd.h>
]], [[char c;
return readlink ("conftest.link", &c, 1) != 1;]])],
[gl_cv_func_readlink_truncate=yes],
[gl_cv_func_readlink_truncate=no],
[case "$host_os" in
# Guess yes on Linux or glibc systems.
linux-* | linux | *-gnu* | gnu*)
gl_cv_func_readlink_truncate="guessing yes" ;;
# Guess no on AIX or HP-UX.
aix* | hpux*)
gl_cv_func_readlink_truncate="guessing no" ;;
# If we don't know, obey --enable-cross-guesses.
*)
gl_cv_func_readlink_truncate="$gl_cross_guess_normal" ;;
esac
])
rm -f conftest.link conftest.lnk2])
case $gl_cv_func_readlink_truncate in
*yes)
if test "$gl_cv_decl_readlink_works" != yes; then
REPLACE_READLINK=1
fi
;;
*)
AC_DEFINE([READLINK_TRUNCATE_BUG], [1], [Define to 1 if readlink
sets errno instead of truncating a too-long link.])
REPLACE_READLINK=1
;;
esac
fi
])
# Like gl_FUNC_READLINK, except prepare for separate compilation
# (no REPLACE_READLINK, no AC_LIBOBJ).
AC_DEFUN([gl_FUNC_READLINK_SEPARATE],
[
AC_CHECK_FUNCS_ONCE([readlink])
gl_PREREQ_READLINK
])
# Prerequisites of lib/readlink.c.
AC_DEFUN([gl_PREREQ_READLINK],
[
:
])
|
