Thanks to Ralf Wildenhues and Stepan Kasal for providing a prompt answer. The correct approach is to use $LIBS instead of $LDFLAGS for library includes and this fixed the problem. I knew I must had done something wrong but could not figure out what. Thanks for your patience, Horst ----- Original Message ----- From: "Horst Wagner" <horst_wagner@xxxxxxx> To: <autoconf@xxxxxxx> Sent: Wednesday, August 10, 2005 10:10 PM Subject: Problem with AC_CHECK_FUNC and order of gcc command-line parameters > Hi, > > I am having trouble with AC_CHECK_FUNC. It turns out that the order of > parameters on the gcc commandline configure uses to compile code to check > for the existence of the function is not proper in my case. > I could not find any mention of such a problem in newsgroups, so I am > assuming I am doing something stupid. > The root problem is that in the compile command the source file name > (conftest.c) is placed behind the $LDFLAGS. Latter library contains the > function I am checking for. > If I reorder the commandline such that -lgd comes after conftest.c (the way > it ought to be according to the gcc documentation) then the code compiles > fine. I observe this problem with both autoconf-2.1.3 and 2.5.9 and am > running on cygwin using gcc3.4.4 > I appreciate any tips on how to resolve this. > > Thanks, > Horst > > > Here is the appropriate excerpt from configure.in > > ============= > LDFLAGS="$LDFLAGS -lgd" > AC_CHECK_FUNC(gdImagePng, DO_GD=' ';AC_DEFINE(DO_GD)) > ============= > > Here is the appropriate excerpt from config.log: > ============= > configure:2242: checking for gdImagePng > configure:2270: gcc -o > ftest -g -O2 -I/usr/X11R6/include -I/usr/local/include -L/usr/X11R6/l > ib -L/usr/local/lib -lm -lX11 -lgd conftest.c 1>&5 > /D/tmp/ccQFB8tX.o: In function `main': > /cygdrive/d/horst/C/g2/g2/configure:2264: undefined reference to > `_gdImagePng' > collect2: ld returned 1 exit status > ============= > > > > > _______________________________________________ > Autoconf mailing list > Autoconf@xxxxxxx > http://lists.gnu.org/mailman/listinfo/autoconf > _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
