=head1 NAME Net::SIP::Debug - debugging of Net::SIP =head1 SYNOPSIS use Net::SIP::Debug '1'; use Net::SIP::Debug qw( Net::SIP*=0 Registrar=1 ); Net::SIP::Debug->level(1); perl -MNet::SIP::Debug=1 app.pl =head1 DESCRIPTION Provides debugging support for L<Net::SIP>. Debugging can be enabled/disabled globally or per package and optional per subpackage. It provides support for different debugging levels, e.g. the higher the level, the more debugging is done. The following levels are used: =over 4 =item 1 - Debug messages for users. =item 2 - Includes short SIP packet dumps of incoming and outgoing data. =item 5 - Includes detailed SIP packet dumps for incoming and outgoing data. =item 10 - Includes information about call flow, e.g. why packets get dropped etc. =item 50 - Detailed debugging for programmers using L<Net::SIP>. =item 100 - Detailed debugging for core developers of L<Net::SIP>. =back =head1 CLASS METHODS =over 4 =item import ( @ARGS ) Extracts everything from arguments given to C<use> which might be usable by B<level> and forwards rest to L<Exporter>. If the argument is a reference to a subroutine it will be used for showing the debug message instead of printing it to STDERR. In this case the usual prefixes incl the time will not be added (useful for forwarding debug to syslog). =item level ( @ARGS ) Enables/disables debugging depending on @ARGS. @ARGS might contain the following specifications: =over 8 =item NUMBER NUMBER will be interpreted as the debugging level. It's used in B<debug> etc to print only debug message which a level lower or equal to NUMBER. =item PACKAGE Enables debugging for package PACKAGE. PACKAGE might be a fully qualified package (e.g. C<Net::SIP::Registrar>) or the C<Net> or C<Net::SIP> might be omitted (C<Registrar>). If a C<*> is added the debugging will also be enabled for subpackages, e.g. C<Endpoint*> will enable debugging for L<Net::SIP::Endpoint> and L<Net::SIP::Endpoint::Context> too. =item PACKAGE=NUMBER Similar to the previous item, but this sets debugging level to NUMBER for the specified packages and thus can also be used to selectively disable debugging for some packages. =back If @ARGS is empty it will return the debugging level for the package which called this method (the first package in the caller stack which is not Net::SIP::Debug itself). =item set_prefix ( PREFIX ) Sets prefix used for debug messages to PREFIX. Default prefix is 'DEBUG:' but for instance for forking applications it might be useful to change this to "DEBUG($$):" or similar. =back =head1 SUBROUTINES =over 4 =item DEBUG|debug ( [ LEVEL ],( MESSAGE | FMT,@ARG )) If debugging is enabled it will print debugging info to STDERR. If multiple arguments are given to the function they will be fed into B<sprintf> to create a single message. If the first argument looks like a number (see B<looks_like_number> in L<Scalar::Util>) it will be interpreted as the debug level for this message, e.g. if it is higher than the user specified debug level the message will not be printed. The MESSAGE (or the result from C<< sprintf(FMT,@ARG) >>) will be prefixed by the caller package, the caller function and the line from which DEBUG was called. In front of the prefix the current time (as float time_t) and the string "DEBUG:" will be added. If the message consists of multiple lines each line will be prefixed by the prefix and all but the first line will also have a TAB added between prefix and message data. The function is by default exported as B<DEBUG> and can by exported as B<debug> too. =item DEBUG_DUMP ( [ LEVEL ], @DATA ) Will call B<debug> with the output from L<Data::Dumper>s B<Dumper> if debugging is enabled. If @DATA has more than one item it will be fed as reference into B<Dumper>, otherwise only the single item will be fed to B<Dumper>. For the meaning of LEVEL see B<debug>. This function is exported by default. =item stacktrace ( MESSAGE | FMT,@ARG ) Uses the arguments in B<debug>, but instead of writing a debug message to STDERR it will be used in Carp::longmess. Returns string with stacktrace. =item LEAK_TRACK ( REF ) This is used internally for tracking leaks. It will rebless REF into a new class which behaves like the old one. Calls of LEAK_TRACK and DESTROY on this class will be tracked and shown. If L<Devel::Peek> can be loaded it will B<Dump> information about the REF on each call to LEAK_TRACK. Exported by default. =back =head1 exported Variables =over 4 =item $DEBUG This variable is set to false if all kind of debugging is disabled. This variable is exported by default. It should not be changed. It is intended to be used as a quick check to save expensive calls of debugging functions if no debugging will be used anyway, i.e.: $DEBUG && DEBUG(...) =back