| # readlink.m4 serial 16 |
| dnl Copyright (C) 2003, 2007, 2009-2021 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], |
| [ |
| : |
| ]) |
