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Re: Re: Embedding Perl in C -- access to builtins?

by premchai21 (Curate)
on May 31, 2002 at 19:54 UTC ( #170817=note: print w/replies, xml ) Need Help??


in reply to Re: Embedding Perl in C -- access to builtins?
in thread Embedding Perl in C -- access to builtins?

That sounds like a good idea.

$ ./reverse
var is narf!
Segmentation fault

Eh?

cat reverse.c

#include <EXTERN.h> #include <perl.h> static PerlInterpreter *my_perl; static SV * do_reverse(x) SV *x; { dSP; int count; SV *var; ENTER; SAVETMPS; PUSHMARK(SP); XPUSHs(sv_mortalcopy(x)); PUTBACK; count = perl_call_pv("CORE::reverse", G_SCALAR); SPAGAIN; if (count != 1) croak("Aieee!"); var = POPs; PUTBACK; FREETMPS; LEAVE; } main (int argc, char **argv, char **env) { STRLEN len; SV *var; my_perl = perl_alloc(); perl_construct(my_perl); var = newSVpvf("%s", "narf!"); printf("var is %s\n", SvPV(var, len)); var = do_reverse(sv_2mortal(var)); printf("var is %s\n", SvPV(var, len)); perl_destruct(my_perl); perl_free(my_perl); }

According to gdb, it's segfaulting on the perl_call_pv. What am I doing wrong?

(Running perl, v5.6.1, built for i686-linux-multi.)

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[tobyink]: You can use grep { $_ =~ /.*$in.*/; } @my_modules but why not stick to grep(/.*$in.*/, @my_modules)? (The latter is faster.)
[shmem]: Lady_Aleena, in the first example grep evaluates the result from grep and if true, returns $_. In the second, it always returns $_
[shmem]: ..the result from the pattern match
[Lady_Aleena]: tobyink, I did after I failed to get the BLOCK to work. I can't seem to get my brain around grep BLOCK, though I'm okay with grep EXPR.
[shmem]: so in the second example grep returns all true elements of the list passed
[Lady_Aleena]: Okay, so grep BLOCK is not like map BLOCK where something might need to be returned at the end.
[tobyink]: grep { $_ =~ /.*$in.*/; } @my_modules should work just fine. The problem is that you were adding on ;$_ at the end of the block. Why were you doing that?
[Lady_Aleena]: tobyink, I was thinking map.
[tobyink]: Something does need to be returned at the end not $_ though. You need to return (something that will be evaluated as) a boolean.
[Lady_Aleena]: Here is a longish map I did in the same script. my @my_modules = map { my $file = $_; $file =~ s/$module_director y(.+)\.pm/$1/; $file =~ s/\//::/g; $file; } @files;

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