NAME¶
Devel::Backtrace - Object-oriented backtrace
VERSION¶
This is version 0.12.
SYNOPSIS¶
my $backtrace = Devel::Backtrace->new;
print $backtrace; # use automatic stringification
# See EXAMPLES to see what the output might look like
print $backtrace->point(0)->line;
METHODS¶
Devel::Backtrace->new()¶
Optional parameters: -start => $start, -format => $format
If only one parameter is given, it will be used as $start.
Constructs a new "Devel::Backtrace" which is filled with all the
information "caller($i)" provides, where $i starts from $start. If
no argument is given, $start defaults to 0.
If $start is 1 (or higher), the backtrace won't contain the information that
(and where)
Devel::Backtrace::new() was called.
$backtrace->point($i)¶
Returns the i'th tracepoint as a Devel::Backtrace::Point object (see its
documentation for how to access every bit of information).
Note that the following code snippet will print the information of
"caller($start+$i)":
print Devel::Backtrace->new($start)->point($i)
$backtrace->points()¶
Returns a list of all tracepoints. In scalar context, the number of tracepoints
is returned.
$backtrace->skipme([$package])¶
This method deletes all leading tracepoints that contain information about calls
within $package. Afterwards the $backtrace will look as though it had been
created with a higher value of $start.
If the optional parameter $package is not given, it defaults to the calling
package.
The effect is similar to what the Carp module does.
This module ships with an example "skipme.pl" that demonstrates how to
use this method. See also "EXAMPLES".
$backtrace->skipmysubs([$package])¶
This method is like "skipme" except that it deletes calls
to
the package rather than calls
from the package.
Before discarding those calls, "skipme" is called. This is because
usually the topmost call in the stack is to Devel::Backtrace->new, which
would not be catched by "skipmysubs" otherwise.
This means that skipmysubs usually deletes more lines than skipme would.
"skipmysubs" was added in Devel::Backtrace version 0.06.
See also "EXAMPLES" and the example "skipme.pl".
$backtrace->to_string()¶
Returns a string that contains one line for each tracepoint. It will contain the
information from "Devel::Backtrace::Point"'s
to_string()
method. To get more information, use the
to_long_string() method.
Note that you don't have to call
to_string() if you print a
"Devel::Backtrace" object or otherwise treat it as a string, as the
stringification operator is overloaded.
See "EXAMPLES".
$backtrace->to_long_string()¶
Returns a very long string that contains several lines for each trace point. The
result will contain every available bit of information. See
"to_long_string" in Devel::Backtrace::Point for an example of what
the result looks like.
EXAMPLES¶
A sample stringification might look like this:
Devel::Backtrace::new called from MyPackage (foo.pl:30)
MyPackage::test2 called from MyPackage (foo.pl:28)
MyPackage::test1 called from main (foo.pl:18)
main::bar called from main (foo.pl:6)
main::foo called from main (foo.pl:13)
If MyPackage called skipme, the first two lines would be removed. If it called
skipmysubs, the first three lines would be removed.
If you don't like the format, you can change it:
my $backtrace = Devel::Backtrace->new(-format => '%I. %s');
This would produce a stringification of the following form:
0. Devel::Backtrace::new
1. MyPackage::test2
2. MyPackage::test1
3. main::bar
4. main::foo
SEE ALSO¶
Devel::StackTrace does mostly the same as this module. I'm afraid I hadn't
noticed it until I uploaded this module.
Carp::Trace is a simpler module which gives you a backtrace in string form.
Devel::DollarAt comes with this distribution and is a nice application of this
module. You can use it for debugging to get a backtrace out of $@.
AUTHOR¶
Christoph Bussenius <pepe@cpan.org>
If you use this module, I'll be glad if you drop me a note. You should mention
this module's name in the subject of your mails, in order to make sure they
won't get lost in all the spam.
LICENSE¶
This module is in the public domain.
If your country's law does not allow this module being in the public domain or
does not include the concept of public domain, you may use the module under
the same terms as perl itself.