# readlink.m4 # serial 18 dnl Copyright (C) 2003, 2007, 2009-2024 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]) AC_CHECK_FUNCS_ONCE([readlink]) if test $ac_cv_func_readlink = no; then HAVE_READLINK=0 else AC_CACHE_CHECK([whether readlink signature is correct], [gl_cv_decl_readlink_works], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM( [[#include /* Cause compilation failure if original declaration has wrong type. */ ssize_t readlink (const char *, char *, size_t); ]]) ], [gl_cv_decl_readlink_works=yes], [gl_cv_decl_readlink_works=no])]) dnl Solaris 9 ignores trailing slash. dnl FreeBSD 7.2 dereferences only one level of links with trailing slash. AC_CACHE_CHECK([whether readlink handles trailing slash correctly], [gl_cv_func_readlink_trailing_slash], [# We have readlink, so assume ln -s works. ln -s conftest.no-such conftest.link ln -s conftest.link conftest.lnk2 AC_RUN_IFELSE( [AC_LANG_PROGRAM( [[#include ]], [[char buf[20]; return readlink ("conftest.lnk2/", buf, sizeof buf) != -1; ]]) ], [gl_cv_func_readlink_trailing_slash=yes], [gl_cv_func_readlink_trailing_slash=no], [case "$host_os" in # Guess yes on Linux or glibc systems. linux-* | linux | *-gnu* | gnu*) gl_cv_func_readlink_trailing_slash="guessing yes" ;; # Guess yes on systems that emulate the Linux system calls. midipix*) 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 "$gl_cv_decl_readlink_works" != yes; then REPLACE_READLINK=1 fi ;; *) AC_DEFINE([READLINK_TRAILING_SLASH_BUG], [1], [Define to 1 if readlink fails to recognize a trailing slash.]) REPLACE_READLINK=1 ;; esac AC_CACHE_CHECK([whether readlink truncates results correctly], [gl_cv_func_readlink_truncate], [# We have readlink, so assume ln -s works. ln -s ab conftest.link AC_RUN_IFELSE( [AC_LANG_PROGRAM( [[#include ]], [[char c; return readlink ("conftest.link", &c, 1) != 1; ]]) ], [gl_cv_func_readlink_truncate=yes], [gl_cv_func_readlink_truncate=no], [case "$host_os" in # Guess yes on Linux or glibc systems. linux-* | linux | *-gnu* | gnu*) gl_cv_func_readlink_truncate="guessing yes" ;; # Guess yes on systems that emulate the Linux system calls. midipix*) 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 dnl On Cygwin 3.3.6, readlink("/dev/null") returns "\\Device\\Null", which dnl is unusable. case "$host_os" in cygwin*) 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], [ : ])