I am writing a perl extension. The details of what it does isn't relevant, but the fact that it core dumps is. In my .xs file, I have the following 

typedef struct {
       ...
       char *line ;
       ...
} parse_data ;

parse_data pd ;

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There is a function that at one point does: 
     pd.line = strdup(s) ;

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What I want to do later is return the string that I have stored, and free up the memory. The following is one example of how I have tried to do it: 
void
get_line ()
       PPCODE:

       EXTEND(SP, 1) ;
       PUSHs (sv_2mortal(newSVpv(pd.line,0))) ;
       free (pd.line) ;
       pd.line = 0 ;

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The problem is with the call to free. If this is included, perl core dumps. The strack trace looks like this: 
emergency_sbrk(blah)
morecore(blah)
Perl_sv_grow(blah)
Perl_sv_catpvn(blah)
Perl_pp_concat(blah)
Perl_runops_standard(blah)

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Moving the call to free to just before where I reassign a new line works, but after the last call, I would end up with a chunk of unfreed memory hanging around. I *thought* that newSVpv allocated the memory to store the string in, and then copied in my string. If it doesn't, and just runs down the pointer I gave it, then it will of course blow up. How can I pass the value out to Perl and not leave allocated memory hanging about? Yours banging head against wall, Nosmo

In reply to Help with Perl Extension by nosmo_1

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