#49648 [Opn->Fbk]: Broken Macro in acinclude.m4

ID: 49648 Updated by: jani@php.net Reported By: sven at whgl dot uni-frankfurt dot de -Status: Open +Status: Feedback -Bug Type: Unknown/Other Function +Bug Type: Compile Failure Operating System: Linux PHP Version: 5.2.11 New Comment: Not enough information. And there's nothing wrong with the macro either, it's been used in dozens of places without any problems. Previous Comments: ------------------------------------------------------------------------ [2009-09-24 03:59:12] sven at whgl dot uni-frankfurt dot de Description: ------------ It seems the PHP_CHEC_LIBRARY Macro wrapping AC_CHECK_LIBRARY is broken for all cases where extra-libs is needed. I'll be quoting directly from the following svn link: http://svn.php.net/viewvc/php/php-src/trunk/acinclude.m4?revision=287126&view=markup --- snip --- Macro Prototype --- 1822 dnl 1823 dnl PHP_CHECK_LIBRARY(library, function [, action-found [, action-not-found [, extra-libs]]]) 1824 dnl 1825 dnl Wrapper for AC_CHECK_LIB 1826 dnl --- snip --- End Proto --- Last Parameter ($5) is extra libs, now we look into the Macro: 1827 AC_DEFUN([PHP_CHECK_LIBRARY], [ 1828 save_old_LDFLAGS=$LDFLAGS 1829 ac_stuff="$5" 1830 1831 save_ext_shared=$ext_shared 1832 ext_shared=yes 1833 PHP_EVAL_LIBLINE([$]ac_stuff, LDFLAGS) 1834 AC_CHECK_LIB([$1],[$2],[ 1835 LDFLAGS=$save_old_LDFLAGS 1836 ext_shared=$save_ext_shared 1837 $3 1838 ],[ 1839 LDFLAGS=$save_old_LDFLAGS 1840 ext_shared=$save_ext_shared 1841 unset ac_cv_lib_$1[]_$2 1842 $4 1843 ])dnl 1844 ]) Instead of passing $5 into $5 of AC_CHECK_LIB some preprocessing is obviously done, LDFLAGS is stored and PHP_EVAL_LIBLINE is called with $5 and $LDFLAGS. This is indeed completely wrong. When we look at the inner workings of PHP_EVAL_LIBLINE, we can see the following: 403 -l*[)] 404 ac_ii=echo $ac_i|cut -c 3- 405 PHP_ADD_LIBRARY($ac_ii,1,$2) 406 ;; 407 -L*[)] 408 ac_ii=echo $ac_i|cut -c 3- 409 PHP_ADD_LIBPATH($ac_ii,$2) Though libs and and lib includes are treated by different Macros, they both operate on $2 and indeed, when using the Macro, libs are added to LDFLAGS, which is not right. The autoconf manual states that: -l<libname> Parameters go into LIBS and only all other linker flags go into LDFLAGS. This is important for the ordering of libs, because AC_CHECK_LIB will prepend the lib to be tested to LIBS, so other-libs, need to be in LIBS, because otherwise the ordering in the call to gcc for the conftest will be wrong and fail. Reproduce code: --------------- PHP_CHECK_LIB(libname,libsymbol,,,other-libs) where libname references symbols from other-libs. Expected result: ---------------- The check should succeed if the libs are in place and gcc should be called properly. Actual result: -------------- The ordering will be wrong, gcc will fail to compile the conftest.c and thus the macro fails although it should net. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=49648&edit=1