Short IT recipes: xampp: Compiling mod_bw.c and getting the error about undefined symbol: apr_atomic

Sunday, February 21, 2010

xampp: Compiling mod_bw.c and getting the error about undefined symbol: apr_atomic_cas

When I was compiling mod_bw.c 0.7 (apxs -i -a -c mod_bw.c) for xampp 1.7.1 on Ubuntu 9.10 and restarting lampp I was getting the following error:

httpd: Syntax error on line 129 of /opt/lampp/etc/httpd.conf: Cannot load /opt/lampp/modules/mod_bw.so into server: /opt/lampp/modules/mod_bw.so: undefined symbol: apr_atomic_cas

The solution was to edit the mod_bw.c and comment out or remove the following lines:

#if (APR_MAJOR_VERSION < 1)
    #define apr_atomic_inc32 apr_atomic_inc
    #define apr_atomic_dec32 apr_atomic_dec
    #define apr_atomic_add32 apr_atomic_add
    #define apr_atomic_cas32 apr_atomic_cas
    #define apr_atomic_set32 apr_atomic_set
#endif

and to recompile the file.

Unfortunately, there was no difference in the file upload speed.