stas 2003/11/14 21:42:22
Modified: src/docs/2.0/user/troubleshooting troubleshooting.pod
src/docs/2.0/user Changes.pod
Log:
A new troubleshooting section on how to resolve "undefined symbol"
problems
Submitted by: Matisse Enzer <[EMAIL PROTECTED]>
Revision Changes Path
1.15 +155 -1
modperl-docs/src/docs/2.0/user/troubleshooting/troubleshooting.pod
Index: troubleshooting.pod
===================================================================
RCS file:
/home/cvs/modperl-docs/src/docs/2.0/user/troubleshooting/troubleshooting.pod,v
retrieving revision 1.14
retrieving revision 1.15
diff -u -u -r1.14 -r1.15
--- troubleshooting.pod 14 Oct 2003 04:09:59 -0000 1.14
+++ troubleshooting.pod 15 Nov 2003 05:42:21 -0000 1.15
@@ -169,6 +169,155 @@
http://httpd.apache.org/docs-2.0/faq/error.html#error.sendfile
+=head2 undefined symbol: apr_table_compress
+
+After a successful mod_perl build, sometimes during the startup or a
+runtime you'd get an "undefined symbol: foo" error. The following is
+one possible scenario to encounter this problem and possible ways to
+resolve it.
+
+Let's say you ran mod_perl's test suite:
+
+ % make test
+
+and got errors, and you looked in the F<error_log> file
+(F<t/logs/error_log>) and saw one or more "undefined symbol" errors,
+e.g.
+
+ % undefined symbol: apr_table_compress
+
+=over
+
+=item Step 1
+
+From the source directory (same place you ran "make test") run:
+
+ % ldd blib/arch/auto/APR/APR.so | grep apr-
+
+META: ldd is not available on all platforms, e.g. not on Darwin/OS X
+
+You you should get a full path, for example:
+
+ libapr-0.so.0 => /usr/local/apache2/lib/libapr-0.so.0 (0x40003000)
+
+or
+
+ libapr-0.so.0 => /some/path/to/apache/lib/libapr-0.so.0 (0x40003000)
+
+or something like that. It's that full path to libapr-0.so.0 that you
+want.
+
+
+=item Step 2
+
+Do:
+
+ % nm /path/to/your/libapr-0.so.0 | grep table_compress
+
+for example:
+
+ % nm /usr/local/apache2/lib/libapr-0.so.0 | grep table_compress
+
+You should get something like this:
+
+ 0000d010 T apr_table_compress
+
+Note that the "grep table_compress" is only an example, the exact
+string you are looking for is the name of the "undefined symbol" from
+the error_log. So, if you got "undefined symbol: apr_holy_grail" then
+you would do
+
+ % nm /usr/local/apache2/lib/libapr-0.so.0 | grep holy_grail
+
+=item Step 3
+
+Now, let's see what shared libraries your apache binary has. So, if in
+step 1 you got F</usr/local/apache2/lib/libapr-0.so.0> then you will
+do:
+
+ % ldd /usr/local/apache2/bin/httpd
+
+if in step 1 you got F</foo/bar/apache/lib/libapr-0.so.0> then you do:
+
+ % ldd /foo/bar/apache/bin/httpd
+
+The output should look something like this:
+
+ libssl.so.2 => /lib/libssl.so.2 (0x40023000)
+ libcrypto.so.2 => /lib/libcrypto.so.2 (0x40054000)
+ libaprutil-0.so.0 => /usr/local/apache2/lib/libaprutil-0.so.0 (0x40128000)
+ libgdbm.so.2 => /usr/lib/libgdbm.so.2 (0x4013c000)
+ libdb-4.0.so => /lib/libdb-4.0.so (0x40143000)
+ libexpat.so.0 => /usr/lib/libexpat.so.0 (0x401eb000)
+ libapr-0.so.0 => /usr/local/apache2/lib/libapr-0.so.0 (0x4020b000)
+ librt.so.1 => /lib/librt.so.1 (0x40228000)
+ libm.so.6 => /lib/i686/libm.so.6 (0x4023a000)
+ libcrypt.so.1 => /lib/libcrypt.so.1 (0x4025c000)
+ libnsl.so.1 => /lib/libnsl.so.1 (0x40289000)
+ libdl.so.2 => /lib/libdl.so.2 (0x4029f000)
+ libpthread.so.0 => /lib/i686/libpthread.so.0 (0x402a2000)
+ libc.so.6 => /lib/i686/libc.so.6 (0x42000000)
+ /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
+
+Those are name =E<gt> value pairs showing the shared libraries used by
+the C<httpd> binary.
+
+Take note of the value for F<libapr-0.so.0> and compare it to what you
+got in step 1. They should be the same, if not, then mod_perl was
+compiled pointing to the wrong Apache installation. You should run
+"make clean" and then
+
+ % perl Makefile.pl MP_APACHE_CONFIG=/path/to/apache/bin/apr-config
+
+using the correct path for the Apache installation.
+
+=item Step 4
+
+You should also search for extra copies of F<libapr-0.so.0>. If you
+find one in I</usr/lib> or I</usr/local/lib> that will explain the
+problem. Most likely you have an old pre-installed apr package which
+gets loaded before the copy you found in step 1.
+
+On most Linux (and Mac OS X) machines you can do a fast search with:
+
+ % locate libapr-0.so.0
+
+which searches a database of files on your machine. The "locate"
+database isn't always up-to-date so a slower, more comprehensive
+search can be run (as root if possible):
+
+ % find / -name "libapr-0.so.0*"
+
+or
+
+ % find /usr/local -name "libapr-0.so.0*"
+
+You might get output like this:
+
+ /usr/local/apache2.0.47/lib/libapr-0.so.0.9.4
+ /usr/local/apache2.0.47/lib/libapr-0.so.0
+ /usr/local/apache2.0.45/lib/libapr-0.so.0.9.3
+ /usr/local/apache2.0.45/lib/libapr-0.so.0
+
+in which case you would want to make sure that you are configuring and
+compiling mod_perl with the latest version of apache, for example
+using the above output, you would do:
+
+ % perl Makefile.PL MP_AP_CONFIG=/usr/local/apache2.0.47
+ % make
+ % make test
+
+
+=back
+
+There could be other causes, but this example shows you how to act
+when you encounter this problem.
+
+
+
+
+
+
=head1 Issues with APR Used Outside of mod_perl
It doesn't strictly belong to this document, since it's talking about
@@ -177,11 +326,16 @@
Whenever using an C<APR::> package outside of mod_perl, you need to:
- use APR;
+ use APR;
in order to load the XS subroutines. For example:
% perl -MApache2 -MAPR -MAPR::UUID -le 'print APR::UUID->new->format'
+
+
+
+
+
=head1 Maintainers
1.2 +5 -0 modperl-docs/src/docs/2.0/user/Changes.pod
Index: Changes.pod
===================================================================
RCS file: /home/cvs/modperl-docs/src/docs/2.0/user/Changes.pod,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -u -r1.1 -r1.2
--- Changes.pod 20 Mar 2002 17:44:04 -0000 1.1
+++ Changes.pod 15 Nov 2003 05:42:22 -0000 1.2
@@ -11,4 +11,9 @@
=head1 ...
+A new troubleshooting section on how to resolve "undefined symbol"
+problems by Matisse Enzer E<lt>matisse E<lt>atE<gt> hamparts.comE<gt>.
+
+
+
=cut
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