perlembed - how to embed perl in your C program



Do you want to:

Use C from Perl?
Read the perlcall manpage and the perlxs manpage.

Use a UNIX program from Perl?
Read about back-quotes and about system and exec in the perlfunc manpage.

Use Perl from Perl?
Read about do and eval and require and use.

Use C from C?
Rethink your design.

Use Perl from C?
Read on...


Compiling your C program

There's one example in each of the eight sections:

Adding a Perl interpreter to your C program

Calling a Perl subroutine from your C program

Evaluating a Perl statement from your C program

Performing Perl pattern matches and substitutions from your C program

Fiddling with the Perl stack from your C program

Maintaining a persistent interpreter

Maintaining multiple interpreter instances

Using Perl modules, which themselves use C libraries, from your C program

This documentation is Unix specific; if you have information about how to embed Perl on other platforms, please send e-mail to <>.

Compiling your C program

If you have trouble compiling the scripts in this documentation, you're not alone. The cardinal rule: COMPILE THE PROGRAMS IN EXACTLY THE SAME WAY THAT YOUR PERL WAS COMPILED. (Sorry for yelling.)

Also, every C program that uses Perl must link in the perl library. What's that, you ask? Perl is itself written in C; the perl library is the collection of compiled C programs that were used to create your perl executable ( /usr/bin/perl or equivalent). (Corollary: you can't use Perl from your C program unless Perl has been compiled on your machine, or installed properly--that's why you shouldn't blithely copy Perl executables from machine to machine without also copying the lib directory.)

When you use Perl from C, your C program will--usually--allocate, ``run'', and deallocate a PerlInterpreter object, which is defined by the perl library.

If your copy of Perl is recent enough to contain this documentation (version 5.002 or later), then the perl library (and EXTERN.h and perl.h, which you'll also need) will reside in a directory that looks like this:


or perhaps just


or maybe something like


Execute this statement for a hint about where to find CORE:

    perl -MConfig -e 'print $Config{archlib}'

Here's how you'd compile the example in the next section, Adding a Perl interpreter to your C program, on my Linux box:

    % gcc -O2 -Dbool=char -DHAS_BOOL -I/usr/local/include 
    -o interp interp.c -lperl -lm

(That's all one line.) On my DEC Alpha running 5.00305, the incantation is a bit different:

    % cc -O2 -Olimit 2900 -DSTANDARD_C -I/usr/local/include 
    -L/usr/local/lib/perl5/alpha-dec_osf/5.00305/CORE -L/usr/local/lib 
    -D__LANGUAGE_C__ -D_NO_PROTO -o interp interp.c -lperl -lm

How can you figure out what to add? Assuming your Perl is post-5.001, execute a perl -V command and pay special attention to the ``cc'' and ``ccflags'' information.

You'll have to choose the appropriate compiler (cc, gcc, et al.) for your machine: perl -MConfig -e 'print $Config{cc}' will tell you what to use.

You'll also have to choose the appropriate library directory (/usr/local/lib/...) for your machine. If your compiler complains that certain functions are undefined, or that it can't locate -lperl, then you need to change the path following the -L. If it complains that it can't find EXTERN.h and perl.h, you need to change the path following the -I.

You may have to add extra libraries as well. Which ones? Perhaps those printed by

   perl -MConfig -e 'print $Config{libs}'

Provided your perl binary was properly configured and installed the ExtUtils::Embed module will determine all of this information for you:

   % cc -o interp interp.c `perl -MExtUtils::Embed -e ccopts -e ldopts`

If the ExtUtils::Embed module isn't part of your Perl distribution, you can retrieve it from (If this documentation came from your Perl distribution, then you're running 5.004 or better and you already have it.)

The ExtUtils::Embed kit on CPAN also contains all source code for the examples in this document, tests, additional examples and other information you may find useful.

Adding a Perl interpreter to your C program

In a sense, perl (the C program) is a good example of embedding Perl (the language), so I'll demonstrate embedding with miniperlmain.c, from the source distribution. Here's a bastardized, non-portable version of miniperlmain.c containing the essentials of embedding:

    #include <EXTERN.h>               /* from the Perl distribution     */
    #include <perl.h>                 /* from the Perl distribution     */

    static PerlInterpreter *my_perl;  /***    The Perl interpreter    ***/

    int main(int argc, char **argv, char **env)
        my_perl = perl_alloc();
        perl_parse(my_perl, NULL, argc, argv, (char **)NULL);

Notice that we don't use the env pointer. Normally handed to perl_parse as its final argument, env here is replaced by NULL, which means that the current environment will be used.

Now compile this program (I'll call it interp.c) into an executable:

    % cc -o interp interp.c `perl -MExtUtils::Embed -e ccopts -e ldopts`

After a successful compilation, you'll be able to use interp just like perl itself:

    % interp
    print "Pretty Good Perl \n";
    print "10890 - 9801 is ", 10890 - 9801;
    Pretty Good Perl
    10890 - 9801 is 1089


    % interp -e 'printf("%x", 3735928559)'

You can also read and execute Perl statements from a file while in the midst of your C program, by placing the filename in argv[1] before calling perl_run().

Calling a Perl subroutine from your C program

To call individual Perl subroutines, you can use any of the perl_call_* functions documented in the the perlcall manpage man page. In this example we'll use perl_call_argv.

That's shown below, in a program I'll call showtime.c.

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

    static PerlInterpreter *my_perl;

    int main(int argc, char **argv, char **env)
        char *args[] = { NULL };
        my_perl = perl_alloc();

        perl_parse(my_perl, NULL, argc, argv, NULL);

        /*** skipping perl_run() ***/

        perl_call_argv("showtime", G_DISCARD | G_NOARGS, args);


where showtime is a Perl subroutine that takes no arguments (that's the G_NOARGS) and for which I'll ignore the return value (that's the G_DISCARD). Those flags, and others, are discussed in the perlcall manpage.

I'll define the showtime subroutine in a file called

    print "I shan't be printed.";

    sub showtime {
        print time;

Simple enough. Now compile and run:

    % cc -o showtime showtime.c `perl -MExtUtils::Embed -e ccopts -e ldopts`

    % showtime

yielding the number of seconds that elapsed between January 1, 1970 (the beginning of the Unix epoch), and the moment I began writing this sentence.

In this particular case we don't have to call perl_run, but in general it's considered good practice to ensure proper initialization of library code, including execution of all object DESTROY methods and package END {} blocks.

If you want to pass arguments to the Perl subroutine, you can add strings to the NULL-terminated args list passed to perl_call_argv. For other data types, or to examine return values, you'll need to manipulate the Perl stack. That's demonstrated in the last section of this document: Fiddling with the Perl stack from your C program.

Evaluating a Perl statement from your C program

One way to evaluate pieces of Perl code is to use perl_eval_sv(). We've wrapped this inside our own perl_eval() function, which converts a command string to an SV, passing this and the G_DISCARD flag to perl_eval_sv().

Arguably, this is the only routine you'll ever need to execute snippets of Perl code from within your C program. Your string can be as long as you wish; it can contain multiple statements; it can employ use, require and do to include external Perl files.

Our perl_eval() lets us evaluate individual Perl strings, and then extract variables for coercion into C types. The following program, string.c, executes three Perl strings, extracting an int from the first, a float from the second, and a char * from the third.

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

   static PerlInterpreter *my_perl;

   I32 perl_eval(char *string)
     return perl_eval_sv(newSVpv(string,0), G_DISCARD);

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

     my_perl = perl_alloc();
     perl_construct( my_perl );

     perl_parse(my_perl, NULL, 3, embedding, NULL);
                                       /** Treat $a as an integer **/
     perl_eval("$a = 3; $a **= 2");
     printf("a = %d\n", SvIV(perl_get_sv("a", FALSE)));

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

                                       /** Treat $a as a string **/
     perl_eval("$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a); ");
     printf("a = %s\n", SvPV(perl_get_sv("a", FALSE), length));


All of those strange functions with sv in their names help convert Perl scalars to C types. They're described in the perlguts manpage.

If you compile and run string.c, you'll see the results of using SvIV() to create an int, SvNV() to create a float, and SvPV() to create a string:

   a = 9
   a = 9.859600
   a = Just Another Perl Hacker

Performing Perl pattern matches and substitutions from your C program

Our perl_eval() lets us evaluate strings of Perl code, so we can define some functions that use it to ``specialize'' in matches and substitutions: match(), substitute(), and matches().

   char match(char *string, char *pattern);

Given a string and a pattern (e.g., m/clasp/ or /\b\w*\b/, which in your C program might appear as ``/\\b\\w*\\b/''), match returns 1 if the string matches the pattern and 0 otherwise.

   int substitute(char *string[], char *pattern);

Given a pointer to a string and an =~ operation (e.g., s/bob/robert/g or tr[A-Z][a-z]), substitute modifies the string according to the operation, returning the number of substitutions made.

   int matches(char *string, char *pattern, char **matches[]);

Given a string, a pattern, and a pointer to an empty array of strings, matches evaluates $string =~ $pattern in an array context, and fills in matches with the array elements (allocating memory as it does so), returning the number of matches found.

Here's a sample program, match.c, that uses all three (long lines have been wrapped here):

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

   static PerlInterpreter *my_perl;
   I32 perl_eval(char *string)
      return perl_eval_sv(newSVpv(string,0), G_DISCARD);
   /** match(string, pattern)
   ** Used for matches in a scalar context.
   ** Returns 1 if the match was successful; 0 otherwise.
   char match(char *string, char *pattern)
     char *command;
     command = malloc(sizeof(char) * strlen(string) + strlen(pattern) + 37);
     sprintf(command, "$string = '%s'; $return = $string =~ %s",
                      string, pattern);
     return SvIV(perl_get_sv("return", FALSE));
   /** substitute(string, pattern)
   ** Used for =~ operations that modify their left-hand side (s/// and tr///)
   ** Returns the number of successful matches, and
   ** modifies the input string if there were any.
   int substitute(char *string[], char *pattern)
     char *command;
     STRLEN length;
     command = malloc(sizeof(char) * strlen(*string) + strlen(pattern) + 35);
     sprintf(command, "$string = '%s'; $ret = ($string =~ %s)",
                      *string, pattern);
     *string = SvPV(perl_get_sv("string", FALSE), length);
     return SvIV(perl_get_sv("ret", FALSE));
   /** matches(string, pattern, matches)
   ** Used for matches in an array context.
   ** Returns the number of matches,
   ** and fills in **matches with the matching substrings (allocates memory!)
   int matches(char *string, char *pattern, char **match_list[])
     char *command;
     SV *current_match;
     AV *array;
     I32 num_matches;
     STRLEN length;
     int i;
     command = malloc(sizeof(char) * strlen(string) + strlen(pattern) + 38);
     sprintf(command, "$string = '%s'; @array = ($string =~ %s)",
                      string, pattern);
     array = perl_get_av("array", FALSE);
     num_matches = av_len(array) + 1; /** assume $[ is 0 **/
     *match_list = (char **) malloc(sizeof(char *) * num_matches);
     for (i = 0; i <= num_matches; i++) {
       current_match = av_shift(array);
       (*match_list)[i] = SvPV(current_match, length);
     return num_matches;
   main (int argc, char **argv, char **env)
     char *embedding[] = { "", "-e", "0" };
     char *text, **match_list;
     int num_matches, i;
     int j;
     my_perl = perl_alloc();
     perl_construct( my_perl );
     perl_parse(my_perl, NULL, 3, embedding, NULL);

     text = (char *) malloc(sizeof(char) * 486); /** A long string follows! **/
     sprintf(text, "%s", "When he is at a convenience store and the bill \
     comes to some amount like 76 cents, Maynard is aware that there is \
     something he *should* do, something that will enable him to get back \
     a quarter, but he has no idea *what*.  He fumbles through his red \
     squeezey changepurse and gives the boy three extra pennies with his \
     dollar, hoping that he might luck into the correct amount.  The boy \
     gives him back two of his own pennies and then the big shiny quarter \
     that is his prize. -RICHH");
     if (match(text, "m/quarter/")) /** Does text contain 'quarter'? **/
       printf("match: Text contains the word 'quarter'.\n\n");
       printf("match: Text doesn't contain the word 'quarter'.\n\n");
     if (match(text, "m/eighth/")) /** Does text contain 'eighth'? **/
       printf("match: Text contains the word 'eighth'.\n\n");
       printf("match: Text doesn't contain the word 'eighth'.\n\n");
     /** Match all occurrences of /wi../ **/
     num_matches = matches(text, "m/(wi..)/g", &match_list);
     printf("matches: m/(wi..)/g found %d matches...\n", num_matches);
     for (i = 0; i < num_matches; i++)
       printf("match: %s\n", match_list[i]);
     for (i = 0; i < num_matches; i++) {
     /** Remove all vowels from text **/
     num_matches = substitute(&text, "s/[aeiou]//gi");
     if (num_matches) {
       printf("substitute: s/[aeiou]//gi...%d substitutions made.\n",
       printf("Now text is: %s\n\n", text);
     /** Attempt a substitution **/
     if (!substitute(&text, "s/Perl/C/")) {
       printf("substitute: s/Perl/C...No substitution made.\n\n");

which produces the output (again, long lines have been wrapped here)

   match: Text contains the word 'quarter'.

   match: Text doesn't contain the word 'eighth'.

   matches: m/(wi..)/g found 2 matches...
   match: will
   match: with

   substitute: s/[aeiou]//gi...139 substitutions made.
   Now text is: Whn h s t  cnvnnc str nd th bll cms t sm mnt lk 76 cnts, 
   Mynrd s wr tht thr s smthng h *shld* d, smthng tht wll nbl hm t gt bck
   qrtr, bt h hs n d *wht*.  H fmbls thrgh hs rd sqzy chngprs nd gvs th by
   thr xtr pnns wth hs dllr, hpng tht h mght lck nt th crrct mnt.  Th by gvs
   hm bck tw f hs wn pnns nd thn th bg shny qrtr tht s hs prz. -RCHH

   substitute: s/Perl/C...No substitution made.

Fiddling with the Perl stack from your C program

When trying to explain stacks, most computer science textbooks mumble something about spring-loaded columns of cafeteria plates: the last thing you pushed on the stack is the first thing you pop off. That'll do for our purposes: your C program will push some arguments onto ``the Perl stack'', shut its eyes while some magic happens, and then pop the results--the return value of your Perl subroutine--off the stack.

First you'll need to know how to convert between C types and Perl types, with newSViv and sv_setnv and newAV and all their friends. They're described in the perlguts manpage.

Then you'll need to know how to manipulate the Perl stack. That's described in the perlcall manpage.

Once you've understood those, embedding Perl in C is easy.

Because C has no built-in function for integer exponentiation, let's make Perl's ** operator available to it (this is less useful than it sounds, because Perl implements ** with C's pow() function). First I'll create a stub exponentiation function in

    sub expo {
        my ($a, $b) = @_;
        return $a ** $b;

Now I'll create a C program, power.c, with a function PerlPower() that contains all the perlguts necessary to push the two arguments into expo() and to pop the return value out. Take a deep breath...

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

    static PerlInterpreter *my_perl;

    static void
    PerlPower(int a, int b)
      dSP;                            /* initialize stack pointer      */
      ENTER;                          /* everything created after here */
      SAVETMPS;                       /* a temporary variable.   */
      PUSHMARK(sp);                   /* remember the stack pointer    */
      XPUSHs(sv_2mortal(newSViv(a))); /* push the base onto the stack  */
      XPUSHs(sv_2mortal(newSViv(b))); /* push the exponent onto stack  */
      PUTBACK;                      /* make local stack pointer global */
      perl_call_pv("expo", G_SCALAR); /* call the function             */
      SPAGAIN;                        /* refresh stack pointer         */
                                    /* pop the return value from stack */
      printf ("%d to the %dth power is %d.\n", a, b, POPi);
      FREETMPS;                       /* free that return value        */
      LEAVE;                       /* ...and the XPUSHed "mortal" args.*/

    int main (int argc, char **argv, char **env)
      char *my_argv[2];

      my_perl = perl_alloc();
      perl_construct( my_perl );

      my_argv[1] = (char *) malloc(10);
      sprintf(my_argv[1], "");

      perl_parse(my_perl, NULL, argc, my_argv, NULL);

      PerlPower(3, 4);                      /*** Compute 3 ** 4 ***/


Compile and run:

    % cc -o power power.c `perl -MExtUtils::Embed -e ccopts -e ldopts`

    % power
    3 to the 4th power is 81.

Maintaining a persistent interpreter

When developing interactive and/or potentially long-running applications, it's a good idea to maintain a persistent interpreter rather than allocating and constructing a new interpreter multiple times. The major reason is speed: since Perl will only be loaded into memory once.

However, you have to be more cautious with namespace and variable scoping when using a persistent interpreter. In previous examples we've been using global variables in the default package main. We knew exactly what code would be run, and assumed we could avoid variable collisions and outrageous symbol table growth.

Let's say your application is a server that will occasionally run Perl code from some arbitrary file. Your server has no way of knowing what code it's going to run. Very dangerous.

If the file is pulled in by perl_parse, compiled into a newly constructed interpreter, and subsequently cleaned out with perl_destruct afterwards, you're shielded from most namespace troubles.

One way to avoid namespace collisions in this scenario is to translate the filename into a guaranteed-unique package name, and then compile the code into that package using eval. In the example below, each file will only be compiled once. Or, the application might choose to clean out the symbol table associated with the file after it's no longer needed. Using perl_call_argv, We'll call the subroutine Embed::Persistent::eval_file which lives in the file and pass the filename and boolean cleanup/cache flag as arguments.

Note that the process will continue to grow for each file that it uses. In addition, there might be AUTOLOADed subroutines and other conditions that cause Perl's symbol table to grow. You might want to add some logic that keeps track of the process size, or restarts itself after a certain number of requests, to ensure that memory consumption is minimized. You'll also want to scope your variables with my whenever possible.

 package Embed::Persistent;
 use strict;
 use vars '%Cache';
 sub valid_package_name {
     my($string) = @_;
     $string =~ s/([^A-Za-z0-9\/])/sprintf("_%2x",unpack("C",$1))/eg;
     # second pass only for words starting with a digit
     $string =~ s|/(\d)|sprintf("/_%2x",unpack("C",$1))|eg;
     # Dress it up as a real package name
     $string =~ s|/|::|g;
     return "Embed" . $string;
 #borrowed from
 sub delete_package {
     my $pkg = shift;
     my ($stem, $leaf);
     no strict 'refs';
     $pkg = "main::$pkg\::";    # expand to full symbol table name
     ($stem, $leaf) = $pkg =~ m/(.*::)(\w+::)$/;
     my $stem_symtab = *{$stem}{HASH};
     delete $stem_symtab->{$leaf};
 sub eval_file {
     my($filename, $delete) = @_;
     my $package = valid_package_name($filename);
     my $mtime = -M $filename;
     if(defined $Cache{$package}{mtime}
        $Cache{$package}{mtime} <= $mtime) 
        # we have compiled this subroutine already, 
        # it has not been updated on disk, nothing left to do
        print STDERR "already compiled $package->handler\n";
     else {
        local *FH;
        open FH, $filename or die "open '$filename' $!";
        local($/) = undef;
        my $sub = <FH>;
        close FH;
        #wrap the code into a subroutine inside our unique package
        my $eval = qq{package $package; sub handler { $sub; }};
            # hide our variables within this block
            eval $eval;
        die $@ if $@;
        #cache it unless we're cleaning out each time
        $Cache{$package}{mtime} = $mtime unless $delete;
     eval {$package->handler;};
     die $@ if $@;
     delete_package($package) if $delete;
     #take a look if you want
     #print Devel::Symdump->rnew($package)->as_string, $/;

 /* persistent.c */
 #include <EXTERN.h> 
 #include <perl.h> 
 /* 1 = clean out filename's symbol table after each request, 0 = don't */
 #ifndef DO_CLEAN
 #define DO_CLEAN 0
 static PerlInterpreter *perl = NULL;
 main(int argc, char **argv, char **env)
     char *embedding[] = { "", "" };
     char *args[] = { "", DO_CLEAN, NULL };
     char filename [1024];
     int exitstatus = 0;
     if((perl = perl_alloc()) == NULL) {
        fprintf(stderr, "no memory!");
     exitstatus = perl_parse(perl, NULL, 2, embedding, NULL);
     if(!exitstatus) { 
        exitstatus = perl_run(perl);
        while(printf("Enter file name: ") && gets(filename)) {
            /* call the subroutine, passing it the filename as an argument */
            args[0] = filename;
                           G_DISCARD | G_EVAL, args);
            /* check $@ */
                fprintf(stderr, "eval error: %s\n", SvPV(GvSV(errgv),na));
     perl_destruct_level = 0;

Now compile:

 % cc -o persistent persistent.c `perl -MExtUtils::Embed -e ccopts -e ldopts` 

Here's a example script file:
 my $string = "hello";

 sub foo {
     print "foo says: @_\n";

Now run:

 % persistent
 Enter file name:
 foo says: hello
 Enter file name:
 already compiled Embed::test_2epl->handler
 foo says: hello
 Enter file name: ^C

Maintaining multiple interpreter instances

Some rare applications will need to create more than one interpreter during a session. Such an application might sporadically decide to release any resources associated with the interpreter.

The program must take care to ensure that this takes place before the next interpreter is constructed. By default, the global variable perl_destruct_level is set to , since extra cleaning isn't needed when a program has only one interpreter.

Setting perl_destruct_level to 1 makes everything squeaky clean:

 perl_destruct_level = 1; 

 while(1) {
     /* reset global variables here with perl_destruct_level = 1 */
     /* clean and reset _everything_ during perl_destruct */
     /* let's go do it again! */

When perl_destruct() is called, the interpreter's syntax parse tree and symbol tables are cleaned up, and global variables are reset.

Now suppose we have more than one interpreter instance running at the same time. This is feasible, but only if you used the -DMULTIPLICITY flag when building Perl. By default, that sets perl_destruct_level to 1.

Let's give it a try:

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

 /* we're going to embed two interpreters */
 /* we're going to embed two interpreters */

 #define SAY_HELLO "-e", "print qq(Hi, I'm $^X\n)"

 int main(int argc, char **argv, char **env)
         *one_perl = perl_alloc(),
         *two_perl = perl_alloc();  
     char *one_args[] = { "one_perl", SAY_HELLO };
     char *two_args[] = { "two_perl", SAY_HELLO };


     perl_parse(one_perl, NULL, 3, one_args, (char **)NULL);
     perl_parse(two_perl, NULL, 3, two_args, (char **)NULL);




Compile as usual:

 % cc -o multiplicity multiplicity.c `perl -MExtUtils::Embed -e ccopts -e ldopts`

Run it, Run it:

 % multiplicity
 Hi, I'm one_perl
 Hi, I'm two_perl

Using Perl modules, which themselves use C libraries, from your C program

If you've played with the examples above and tried to embed a script that use()s a Perl module (such as Socket) which itself uses a C or C++ library, this probably happened:

 Can't load module Socket, dynamic loading not available in this perl.
  (You may need to build a new perl executable which either supports
  dynamic loading or has the Socket module statically linked into it.)

What's wrong?

Your interpreter doesn't know how to communicate with these extensions on its own. A little glue will help. Up until now you've been calling perl_parse(), handing it NULL for the second argument:

 perl_parse(my_perl, NULL, argc, my_argv, NULL);

That's where the glue code can be inserted to create the initial contact between Perl and linked C/C++ routines. Let's take a look some pieces of perlmain.c to see how Perl does this:

 #ifdef __cplusplus
 #  define EXTERN_C extern "C"
 #  define EXTERN_C extern

 static void xs_init _((void));

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

 EXTERN_C void
        char *file = __FILE__;
        /* DynaLoader is a special case */
        newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
        newXS("Socket::bootstrap", boot_Socket, file);

Simply put: for each extension linked with your Perl executable (determined during its initial configuration on your computer or when adding a new extension), a Perl subroutine is created to incorporate the extension's routines. Normally, that subroutine is named Module::bootstrap() and is invoked when you say use Module. In turn, this hooks into an XSUB, boot_Module, which creates a Perl counterpart for each of the extension's XSUBs. Don't worry about this part; leave that to the xsubpp and extension authors. If your extension is dynamically loaded, DynaLoader creates Module::bootstrap() for you on the fly. In fact, if you have a working DynaLoader then there is rarely any need to link in any other extensions statically.

Once you have this code, slap it into the second argument of perl_parse():

 perl_parse(my_perl, xs_init, argc, my_argv, NULL);

Then compile:

 % cc -o interp interp.c `perl -MExtUtils::Embed -e ccopts -e ldopts`

 % interp
   use Socket;
   use SomeDynamicallyLoadedModule;

   print "Now I can use extensions!\n"'

ExtUtils::Embed can also automate writing the xs_init glue code.

 % perl -MExtUtils::Embed -e xsinit -- -o perlxsi.c
 % cc -c perlxsi.c `perl -MExtUtils::Embed -e ccopts`
 % cc -c interp.c  `perl -MExtUtils::Embed -e ccopts`
 % cc -o interp perlxsi.o interp.o `perl -MExtUtils::Embed -e ldopts`

Consult the perlxs manpage and the perlguts manpage for more details.


You can sometimes write faster code in C, but you can always write code faster in Perl. Because you can use each from the other, combine them as you wish.


Jon Orwant and <> and Doug MacEachern <>, with small contributions from Tim Bunce, Tom Christiansen, Hallvard Furuseth, Dov Grobgeld, and Ilya Zakharevich.

Check out Doug's article on embedding in Volume 1, Issue 4 of The Perl Journal. Info about TPJ is available from

February 1, 1997

Some of this material is excerpted from Jon Orwant's book: Perl 5 Interactive, Waite Group Press, 1996 (ISBN 1-57169-064-6) and appears courtesy of Waite Group Press.


Copyright (C) 1995, 1996, 1997 Doug MacEachern and Jon Orwant. All Rights Reserved.

Although destined for release with the standard Perl distribution, this document is not public domain, nor is any of Perl and its documentation. Permission is granted to freely distribute verbatim copies of this document provided that no modifications outside of formatting be made, and that this notice remain intact. You are permitted and encouraged to use its code and derivatives thereof in your own source code for fun or for profit as you see fit.