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Module not returning a true value

Module not returning a true value

Module not returning a true value

What's all this about??

$ ./trace_test.pl
TRACING.pm did not return a true value at ./trace_test.pl line 4.
BEGIN failed--compilation aborted at ./trace_test.pl line 4.

I have exported my functions and variables using the @EXPORT thing.. I copied an example module and then modified it with my code. But when my test script above tries to run a function I get the error message above.

Is this a silly syntactical error? Or does it mean something more serious?


RE: Module not returning a true value

When you include a module in your perl program, the module (.pl or .pm) must always return a value of true.  Any other value indicates that the module has failed in some way.  For example, a compilation problem, or you may have initialisation code in the module that has failed and manually return a value of false.

I don't have any experience with writing "modern" (;^) .pm style OOP modules, as I usually just create function libraries.  ie, a seperate perl file just containing various functions.  At the end of each "function library", I simply enter "1;" on a line on it's own at the end of the file.

Try doing the same with your module, it should get rid of that error message you are receiving.

0 1 - Just my two bits

RE: Module not returning a true value

Cheers, it has indeed. I finally decided to download some
modules from the net and after looking through found the 1;s at the bottom of each file. I tried it and lo and behold it worked!

Thanks for the explanation, no books or tutorials I've seen have given any indication of requiring a return value and stuff.

Thanks again!

RE: Module not returning a true value

Showing my age a little, I think it was in the original "pink book" version of Programming Perl.  I'm not 100% sure that I've seen it in the 2nd edition, but I'll check tonight.

Glad it worked for you, though. :)

0 1 - Just my two bits

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