We’ve encountered some problems with mysql detection in NDOUtils – it doesn’t work on one of our redhat servers. The specific problem is that the ceil function is not found, which is because -lm is missing from the list of libraries to add at link time:


utils.o(.text+0x14e): In function `ndo_dbuf_strcat':
: undefined reference to `ceil'
collect2: ld returned 1 exit status


Rather than adding that library in manually (along with the -lz library that we found earlier for Mac OS X), we should use information from mysql_config to construct the compile flags. However, this is a bit tricky because of the various permutations.

Fortunately, the Nagios Plugins have a solution already. They have an m4 file, called np_mysqlclient.m4, that is used to detect mysql_config and this returns data from the msyql_config for configure to use.

So we’ve patched NDOUtils so that it uses this m4 file now. In order to use, you have to apply the patch to configure.in, add a new m4/ directory to the top level and copy np_mysqlclient.m4 into m4/. Then run:

aclocal -I m4
autoconf
./configure --with-mysql=DIR


The detection is the same as in the Nagios Plugins: ./configure will try to find mysql_config in DIR/bin/mysql_config, otherwise will look in the PATH.

The nice thing is that if the logic for detection needs to be enhanced, we can update the m4 file and propagate the changes back to the Nagios Plugins as well. So everyone wins!

There’s also a patch for CFLAGS in src/Makefile.in (which were getting overridden – presumably for testing), a small header change in config.h.in and some Makefile.in changes because make errors were getting lost by the cd .. command.

We’ve tested this on a Mac OS X server, a Debian Etch server, and 32bit and 64bit Redhat, and it is looking good.

Unfortunately, it means deprecating the –with-mysql-inc and –with-mysql-lib configure options. Hopefully, you’ll see why this way is so much nicer.

Here’s the patch against CVS HEAD.

Update: Here’s the patch, reworked for NDOutils 1.4b3

Update: You can get the tarball with just this patch here