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Date: Thu, 1 Nov 2001 12:03:24 +1100
From: Stanley Hopcroft <Stanley DOT Hopcroft AT IPAustralia DOT gov DOT au>
To: Cygwin AT Cygwin DOT COM
Subject: Has anyone compiled XSUBs or embedded the Perl interp with ExtUtils::Embed -e ccopts ..
Message-ID: <20011101120323.B3921@IPAustralia.Gov.AU>
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Dear Ladies and Gentlemen,

I am writing to ask if anyone has compiled a Perl XSUB or built C 
applications with an embedded Perl Interpreter using the ExtUtils::Embed 
module ?

The perlembed man pages recommend compiling an application with an 
embedded Perl interpeter by

gcc -o x x.c `perl -MExtUtils::Embed -e ccopts -e ldopts`

However, while I have an application that compiles (and runs) under
Unix(FreeBSD)  perl 5.0005_03, it complains about

missing library lperl (probably harmless) and 
undefined symbol my_perl 

(the application has no symbol my_perl in it's source), under Perl 5.6.1 
and Cygnus (very recent distro).

If I put dTHX before dSP (as has been recommended) there are heaps of 
undefined symbols from the Dynaloader.

I realise that this is lacking somewhat in detail. I will gladly send
more if necessary.

At this stage I do not know whether the problem is in the code, or in 
the environment. Unfortunately I have no reference Perl 5.6.1 system to 
test against. 

You can see the application below.


-- 
------------------------------------------------------------------------
Stanley Hopcroft	IP Australia
Network Specialist
+61 2 6283 3189	+61 2 6281 1353 (FAX)	Stanley DOT Hopcroft AT IPAustralia DOT Gov DOT AU
------------------------------------------------------------------------
Flugg's Law:
	When you need to knock on wood is when you realize that the
world is composed of vinyl, naugahyde and aluminum.

#include <EXTERN.h>
#include <perl.h>
#include <fcntl.h>
#include <string.h>

/* include PERL xs_init code for module and C library support */

#if defined(__cplusplus)
#define is_cplusplus
#endif

#ifdef is_cplusplus
extern "C" {
#endif

#define NO_XSLOCKS
#include <XSUB.h>

#ifdef is_cplusplus
}
#  ifndef EXTERN_C
#    define EXTERN_C extern "C"
#  endif
#else
#  ifndef EXTERN_C
#    define EXTERN_C extern
#  endif
#endif
 
EXTERN_C void xs_init _((void));

EXTERN_C void boot_DynaLoader _((CV* cv));

EXTERN_C void
xs_init(void)
{
	char *file = __FILE__;
	dXSUB_SYS;

	/* DynaLoader is a special case */
	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
}

static PerlInterpreter *perl = NULL;


int main(int argc, char **argv, char **env){
	char *embedding[] = { "", "p1.pl" };
	char plugin_output[1024];
	char buffer[512];
	char tmpfname[32];
	char fname[32];
	char *args[] = {"","0", "", "", NULL };
	FILE *fp;

	char command_line[80];
        char *ap ;
	int exitstatus;
	int pclose_result;
	dSP; 

	if((perl=perl_alloc())==NULL){
		snprintf(buffer,sizeof(buffer),"Error: Could not allocate memory for embedded Perl interpreter!\n");
		buffer[sizeof(buffer)-1]='\x0';
		printf("%s\n", buffer);
		exit(1);
	}
	perl_construct(perl);
	exitstatus=perl_parse(perl,xs_init,2,embedding,NULL);
	if(!exitstatus) {

		exitstatus=perl_run(perl);

	        while(printf("Enter file name: ") && fgets(command_line, 80, stdin)) {

	                /* call the subroutine, passing it the filename as an argument */

			command_line[strlen(command_line) -1] = '\0';

                        strncpy(fname,command_line,strcspn(command_line," "));
                        fname[strcspn(command_line," ")] = '\x0';
                        args[0] = fname ;
                        args[3] = command_line + strlen(fname) + 1 ;

                        /* generate a temporary filename to which stdout can be redirected. */
                        sprintf(tmpfname,"/tmp/embedded%d",getpid());
                        args[2] = tmpfname;

			/* call our perl interpreter to compile and optionally cache the command */
			perl_call_argv("Embed::Persistent::eval_file", G_DISCARD | G_EVAL, args);

			perl_call_argv("Embed::Persistent::run_package", G_DISCARD | G_EVAL, args);
			
			/* check return status  */
			if(SvTRUE(ERRSV)){
				pclose_result=-2;
				printf("embedded perl ran %s with error %s\n",fname,SvPV(ERRSV,PL_na));
			}
			
			/* read back stdout from script */
			fp=fopen(tmpfname, "r");
			
			/* default return string in case nothing was returned */
			strcpy(plugin_output,"(No output!)");
			
			fgets(plugin_output,sizeof(plugin_output)-1,fp);
			plugin_output[sizeof(plugin_output)-1]='\x0';
			fclose(fp);
			unlink(tmpfname);    
			printf("embedded perl plugin output was %d,%s\n",pclose_result, plugin_output);

		}

	}

	
        PL_perl_destruct_level = 0;
        perl_destruct(perl);
        perl_free(perl);
        exit(exitstatus);
}

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