= Perl Mapscript 3.5+ Debugging =

== Submitted by Aaron D. Hunt <hunt@zedxinc.com> ==
{{{
    $ENV{MS_ERRORFILE} = "/var/log/mapserver.log"; # map engine error log 
}}}
    near the top of the perl mapscript code... before 
    you initialize your map object. 
    This is an environment variable: MS_ERRORFILE 
    for the shell, or execution instance which catches 
    all of the errors/warning that occur within mapserver 
    and sends them to the filespec defined. This one is 
    the *most* useful log for debugging mapfile errors, 
    index problems, and mapserver internals, etc. 
{{{
    WEB 
    log "/var/log/mapserver_access.log 
    END 
}}}
    in the mapfile. you could probably setup that variable in 
    mapscript as well, but I have always put it in the mapfile. 
    It records a set of variables similar to the 
    apache access log for each mapserver execution. 

== Submitted by Lowell.Filak <lfilak@medinaco.org> ==
{{{
    #!/usr/bin/perl -w 

    -w posts all Perl warnings to the httpd log file, 
    usually named error_log in /var/log/httpd or /etc/httpd/logs. 
}}}
== Submitted, in part, by Frank Warmerdam <warmerdam@pobox.com> ==
{{{
    /sbin/ldconfig -v 
}}}
    will give information concerning the shared libraries present 
    on your system. 
{{{
    echo $LD_LIBRARY_PATH 
}}}
    Will give information on the library path traversed when 
    linking. 
{{{
    locate <library_name_ie._gd.h> 
}}}
    Will give location(s) of the specified filename. 

    Does the above information show a mixture of include files 
    (different revisions of the same library). 

== Submitted by Daniel Morissette <dmorissette@mapgears.com> ==
{{{
    ldd mapserv 
}}}
    Look for the path that is listed. 
    Then make sure this path is part of your runtime library path, 
    for this you have two options, assuming you're running Linux: 

    1- add the path to /etc/ld.so.conf and run 'ldconfig' as root 

    or 

    2- Use !SetEnv LD_LIBRARY_PATH to specify this path in your 
    apache httpd.conf 

If when running ./mapserv you receive the error message:
{{{
    mapserv:error while loading libraries:libproj.so.0 cannot open shared object file : No such file or directory. 
}}}
    Run '/sbin/ldconfig -v | grep libproj'.

        Which should return something similar to "libproj.so.0" 
        If not try reinstalling proj.4 

== Submitted by Daniel Morissette <dmorissette@mapgears.com> ==

    If when running ./mapserv you recieve the error message: 
{{{
    error while loading shared libraries :/usr/libwwwappp.so.0 undefined symbol: HTZlib_inflate 
}}}
    Check /usr/lib and /usr/local/lib for a copy of w3c-libwww. 
    If both have a copy then remove the copy in /usr/lib. 
    The cleanest way to remove, is to 'rpm -q -a | grep w3c-libwww' & do 'rpm -e w3c-libwww-<version_number>'. 

If you end up with a "core" file from an error and have the GNU debugger installed:
{{{
    gdb 
    target core ./core 
    backtrace 
}}}