1App::FatPacker::Trace(3U)ser Contributed Perl DocumentatiAopnp::FatPacker::Trace(3)
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6 App::FatPacker::Trace - Tracing module usage using compilation checking
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9 # open STDERR for writing
10 # will be like: open my $fh, '>', '&STDERR'...
11 perl -MApp::FatPacker::Trace=>&STDERR myscript.pl
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13 # open a file for writing
14 # will be like: open my $fh, '>>', 'fatpacker.trace'
15 perl -MApp::FatPacker::Trace=>>fatpacker.trace myscript.pl
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18 This module allows tracing the modules being used by your code. It does
19 that using clever trickery using the "import" method, the "CHECK" block
20 and B's "minus_c" function.
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22 When App::FatPacker::Trace is being used, the import() method will call
23 "B::minus_c" in order to set up the global compilation-only flag perl
24 (the interpreter) has. This will prevent any other code from being run.
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26 Then in the "CHECK" block which is reached at the end of the
27 compilation phase (see perlmod), it will gather all modules that have
28 been loaded, using %INC, and will write it to a file or to STDERR,
29 determined by parameters sent to the "import" method.
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32 import
33 This method gets run when you just load App::FatPacker::Trace. It will
34 note the current %INC and will set up the output to be written to, and
35 raise the compilation-only flag, which will prevent anything from being
36 run past that point. This flag cannot be unset, so this is most easily
37 run from the command line as such:
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39 perl -MApp::FatPacker::Trace [...]
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41 You can control the parameters to the import using an equal sign, as
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44 # send the parameter "hello"
45 perl -MApp::FatPacker::Trace=hello [...]
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47 # send the parameter ">&STDERR"
48 perl -MApp::FatPacker::Trace=>&STDERR [...]
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50 The import method accepts a first parameter telling it which output to
51 open and how. These are both sent in a single parameter.
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53 # append to mytrace.txt
54 perl -MApp::FatPacker::Trace=>>mytrace.txt myscript.pl
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56 # write to STDERR
57 perl -MApp::FatPacker::Trace=>&STDERR myscript.pl
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59 The import method accepts additional parameters of extra modules to
60 load. It will then add these modules to the trace. This is helpful if
61 you want to explicitly indicate additional modules to trace, even if
62 they aren't used in your script. Perhaps you're conditionally using
63 them, perhaps they're for additional features, perhaps they're loaded
64 lazily, whatever the reason.
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66 # Add Moo to the trace, even if you don't trace it in myscript.pl
67 perl -MApp::FatPacker::Trace=>&STDERR,Moo myscript.pl
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71perl v5.36.0 2023-01-19 App::FatPacker::Trace(3)