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-rw-r--r--gl/m4/readlink.m4114
1 files changed, 114 insertions, 0 deletions
diff --git a/gl/m4/readlink.m4 b/gl/m4/readlink.m4
new file mode 100644
index 0000000..d1dd521
--- /dev/null
+++ b/gl/m4/readlink.m4
@@ -0,0 +1,114 @@
+# readlink.m4 serial 16
+dnl Copyright (C) 2003, 2007, 2009-2022 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],
+[
+ :
+])