smack has asked for the wisdom of the Perl Monks concerning the following question:

Good day fellow monks,

I need a bit of assistance embedding a perl script into a C++ console application. I am using Microsoft Visual C++(Not by choice). I am able to embed a perl interpreter that seems to work. The following code functions properly: 

#include <stdafx.h>
#include <EXTERN.h>
#include <perl.h>

static PerlInterpreter *my_perl;

int main (int argc, char **argv, char **env)
   {
       STRLEN n_a;
       char *embedding[] = { "", "-e", "0" };

       my_perl = perl_alloc();
       perl_construct( my_perl );

       perl_parse(my_perl, NULL, 3, embedding, NULL);
       perl_run(my_perl);

       /** Treat $a as an integer **/
       eval_pv("$a = 3; $a **= 2", TRUE);
       printf("a = %d\n", SvIV(get_sv("a", FALSE)));

       /** Treat $a as a float **/
       eval_pv("$a = 3.14; $a **= 2", TRUE);
       printf("a = %f\n", SvNV(get_sv("a", FALSE)));

       /** Treat $a as a string **/
       eval_pv("$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a);", T
+RUE);
       printf("a = %s\n", SvPV(get_sv("a", FALSE), n_a));

       perl_destruct(my_perl);
       perl_free(my_perl);
        return 0;
    }

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However, I am unable to access prewritten perl functions. Here is the code I have been attempting to get to work: 
#include "stdafx.h"
#include <EXTERN.h>
#include <perl.h>

static PerlInterpreter *my_perl;


static void call_PrintUID()
{
    dSP ;
    PUSHMARK(SP) ;
    call_pv("PrintUID", G_DISCARD|G_NOARGS) ;
}

int main (int argc, char **argv, char **env)
{


    char *embedding[] = { "", "printuid.pl" };

    my_perl = perl_alloc();
    perl_construct( my_perl );
    perl_parse(my_perl, NULL, 3, embedding, NULL);
    perl_run(my_perl);
    call_PrintUID();
    perl_destruct(my_perl);
    perl_free(my_perl);
    return 0;
}

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I haven't used C/C++ in a long time and was never that great at it anyways, so this is very frustrating. If anyone could help me figure out where I am going wrong I would GREATLY appreciate it. =)

Best Regards!
smack

Replies are listed 'Best First'.
Re: Embedding perl into a win32 console application
by Anonymous Monk on Oct 07, 2004 at 21:45 UTC
    You might want to take a look at the perlembed-POD (full title: 'how to embed perl in your C program')
    (If you haven't done so already)
[reply]
Re: Embedding perl into a win32 console application
by kutsu (Priest) on Oct 07, 2004 at 21:52 UTC

    I assume perl_alloc(); is in perl.h which you haven't posted, so I'm not sure why it, and the other methods, aren't working. Actually, instead of writing it yourself, you might try ExtUtils::Embed.

    "Cogito cogito ergo cogito sum - I think that I think, therefore I think that I am." Ambrose Bierce

[reply]
Re: Embedding perl into a win32 console application
by gmpassos (Priest) on Oct 08, 2004 at 01:42 UTC
    You should take a look at perlcall, perlapi and perlguts.

    But since I was working on something similar for PLJava and PLDelphi, here's some snippets with some extra comments: 

    char*
EmbedPerl_call_args( char* code , char* arg1 ) {
  // dTHX enables multiple Perl interpreters for the API functions:
  dTHX ;
  // Enables the call of sub from C (handles @_ and returned values):
  dSP ;

  char *tmp , *retval ;
  SV* ret ;
  
  // Enable the call of the function from multiple native threads:
  PERL_SET_CONTEXT(PL_curinterp) ;

  // enter and save tmp to enable call to perl function (handles @_ fo
+r us):
  ENTER ;
  SAVETMPS ;

    // Enable the insertion of arguments to send to the sub call:
    PUSHMARK(SP) ;
      // add arg1 as a new SV in the arguments (@_):
      XPUSHs(sv_2mortal(newSVpv(arg1, strlen(arg1))));
    PUTBACK ;
  
    // call the sub:
    call_pv(code , G_SCALAR);

    // refresh returneds to get returned value:
    SPAGAIN ;

    // get the SV returned (SCALAR context):
    ret = POPs ;
    
    // tmp will point to the internal char* of the SCALAR, so,
    // when we clean the scalar we clean tmp, and can't return it...
    tmp = SvPV(ret , len) ;
    // ... so, we copy tmp to retval to can return the char* after cle
+an tmps:
    retval = malloc(sizeof(char) * (len+1)) ;
    Copy(tmp, retval, len, char);
    // add end of char*:
    retval[len] = '\0';
  
  // clean tmps and return to the previous state:
  FREETMPS ;
  LEAVE ;

  // the returned value:
  return retval  ;
}

    [download]
    You also can take a look at the sources of LibZip, at ./myldr/ and ./myldr/zlib-src/main.c to see sources of an executable that do that and for a MakeFile.PL that compile automatically your app on Linux and Windows.

    Enjoy!

    Graciliano M. P.
    "Creativity is the expression of the liberty".

[reply]
[d/l]

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