in Perl

more Perl aggravation…

For some time I’ve been trying to get amavisd-new to play nicely with ClamAV using Mail::ClamAV under FreeBSD. It just would not behave – I would get an error like /usr/local/lib/ undefined reference to pthread_mutex_create() and fall over. (This error message would only appear if amavisd-new was being run in debug mode; otherwise, mail would just silently fail to be delivered and queue forever.)

Well, I finally discovered the problem: Perl is not built multithreaded by default on FreeBSD! 🙁 You have to build Perl, defining WITH_THREADS and this will work.

Obviously this isn’t apparent from the above error message. It looks like ClamAV is the culprit, rather than the that’s built by Mail::ClamAV. I guess it’s just because in the course of using the ClamAV API, is the caller, so the runtime link problem is wrongly attributed to it.

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  1. It is very apparent from the error message. Here is how:
    1. There is an undefined reference to pthread_mutex_create().
    2. So where is pthread_mutex_create() defined? In the pthread lib.
    3. The executable that you are running is amavisd-new, which is actually Perl. So when the Perl binary is executed, the runtime linker can't find pthread_mutex_create(), leading to the "undefined reference" error.
    4. So clearly Perl was not linked with the threading library, which "perl -V" would have confirmed.