=item B<Use C from Perl?>
-Read L<perlcall> and L<perlxs>.
+Read L<perlxstut>, L<perlxs>, L<h2xs>, and L<perlguts>.
-=item B<Use a UNIX program from Perl?>
+=item B<Use a Unix program from Perl?>
Read about back-quotes and about C<system> and C<exec> in L<perlfunc>.
=item B<Use Perl from Perl?>
-Read about L<perlfunc/do> and L<perlfunc/eval> and L<perlfunc/require>
+Read about L<perlfunc/do> and L<perlfunc/eval> and L<perlfunc/require>
and L<perlfunc/use>.
=item B<Use C from C?>
=head2 ROADMAP
-L<Compiling your C program>
+=over 5
-There's one example in each of the eight sections:
+L<Compiling your C program>
L<Adding a Perl interpreter to your C program>
L<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 <F<orwant@tpj.com>>.
+L<Embedding Perl under Win32>
+
+=back
=head2 Compiling your C program
perl -MConfig -e 'print $Config{archlib}'
-Here's how you'd compile the example in the next section,
+Here's how you'd compile the example in the next section,
L<Adding a Perl interpreter to your C program>, on my Linux box:
- % gcc -O2 -Dbool=char -DHAS_BOOL -I/usr/local/include
+ % gcc -O2 -Dbool=char -DHAS_BOOL -I/usr/local/include
-I/usr/local/lib/perl5/i586-linux/5.003/CORE
- -L/usr/local/lib/perl5/i586-linux/5.003/CORE
+ -L/usr/local/lib/perl5/i586-linux/5.003/CORE
-o interp interp.c -lperl -lm
-(That's all one line.) On my DEC Alpha running 5.00305, the incantation
-is a bit different:
+(That's all one line.) On my DEC Alpha running old 5.003_05, the
+incantation is a bit different:
- % cc -O2 -Olimit 2900 -DSTANDARD_C -I/usr/local/include
- -I/usr/local/lib/perl5/alpha-dec_osf/5.00305/CORE
- -L/usr/local/lib/perl5/alpha-dec_osf/5.00305/CORE -L/usr/local/lib
+ % cc -O2 -Olimit 2900 -DSTANDARD_C -I/usr/local/include
+ -I/usr/local/lib/perl5/alpha-dec_osf/5.00305/CORE
+ -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 C<perl -V> command and pay special attention to the "cc" and
-"ccflags" information.
+"ccflags" information.
-You'll have to choose the appropriate compiler (I<cc>, I<gcc>, et al.) for
+You'll have to choose the appropriate compiler (I<cc>, I<gcc>, et al.) for
your machine: C<perl -MConfig -e 'print $Config{cc}'> will tell you what
-to use.
+to use.
You'll also have to choose the appropriate library directory
(I</usr/local/lib/...>) for your machine. If your compiler complains
perl -MConfig -e 'print $Config{libs}'
-Provided your perl binary was properly configured and installed the
+Provided your perl binary was properly configured and installed the
B<ExtUtils::Embed> module will determine all of this information for
you:
If the B<ExtUtils::Embed> module isn't part of your Perl distribution,
you can retrieve it from
-http://www.perl.com/perl/CPAN/modules/by-module/ExtUtils::Embed. (If
+http://www.perl.com/perl/CPAN/modules/by-module/ExtUtils/. (If
this documentation came from your Perl distribution, then you're
running 5.004 or better and you already have it.)
The B<ExtUtils::Embed> kit on CPAN also contains all source code for
-the examples in this document, tests, additional examples and other
+the examples in this document, tests, additional examples and other
information you may find useful.
=head2 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 I<miniperlmain.c>,
-from the source distribution. Here's a bastardized, non-portable
+included in the source distribution. Here's a bastardized, nonportable
version of I<miniperlmain.c> containing the essentials of embedding:
#include <EXTERN.h> /* from the Perl distribution */
You can also read and execute Perl statements from a file while in the
midst of your C program, by placing the filename in I<argv[1]> before
-calling I<perl_run()>.
+calling I<perl_run>.
=head2 Calling a Perl subroutine from your C program
To call individual Perl subroutines, you can use any of the B<perl_call_*>
-functions documented in the L<perlcall> man page.
-In this example we'll use
I<perl_call_argv>.
+functions documented in L<perlcall>.
+In this example we'll use
C<perl_call_argv>.
That's shown below, in a program I'll call I<showtime.c>.
=head2 Evaluating a Perl statement from your C program
-One way to evaluate pieces of Perl code is to use
-L<perlguts/perl_eval_sv()>. We've wrapped this inside our own
-I<perl_eval()> function, which converts a command string to an SV,
-passing this and the L<perlcall/G_DISCARD> flag to
-L<perlguts/perl_eval_sv()>.
+Perl provides two API functions to evaluate pieces of Perl code.
+These are L<perlguts/perl_eval_sv> and L<perlguts/perl_eval_pv>.
-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
-L<perlfunc/use>, L<perlfunc/require> and L<perlfunc/do> to include
-external Perl files.
+Arguably, these are the only routines you'll ever need to execute
+snippets of Perl code from within your C program. Your code can be as
+long as you wish; it can contain multiple statements; it can employ
+L<perlfunc/use>, L<perlfunc/require>, and L<perlfunc/do> to
+include external Perl files.
-Our I<perl_eval()> lets us evaluate individual Perl strings, and then
+I<perl_eval_pv> lets us evaluate individual Perl strings, and then
extract variables for coercion into C types. The following program,
I<string.c>, executes three Perl strings, extracting an C<int> from
the first, a C<float> from the second, and a C<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);
- perl_run(my_perl);
- /** 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));
-
- perl_destruct(my_perl);
- perl_free(my_perl);
+ 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 $a as an integer **/
+ perl_eval_pv("$a = 3; $a **= 2", TRUE);
+ printf("a = %d\n", SvIV(perl_get_sv("a", FALSE)));
+
+ /** Treat $a as a float **/
+ perl_eval_pv("$a = 3.14; $a **= 2", TRUE);
+ printf("a = %f\n", SvNV(perl_get_sv("a", FALSE)));
+
+ /** Treat $a as a string **/
+ perl_eval_pv("$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a);", TRUE);
+ printf("a = %s\n", SvPV(perl_get_sv("a", FALSE), n_a));
+
+ perl_destruct(my_perl);
+ perl_free(my_perl);
}
All of those strange functions with I<sv> in their names help convert Perl scalars to C types. They're described in L<perlguts>.
a = 9.859600
a = Just Another Perl Hacker
+In the example above, we've created a global variable to temporarily
+store the computed value of our eval'd expression. It is also
+possible and in most cases a better strategy to fetch the return value
+from I<perl_eval_pv()> instead. Example:
+
+ ...
+ STRLEN n_a;
+ SV *val = perl_eval_pv("reverse 'rekcaH lreP rehtonA tsuJ'", TRUE);
+ printf("%s\n", SvPV(val,n_a));
+ ...
+
+This way, we avoid namespace pollution by not creating global
+variables and we've simplified our code as well.
=head2 Performing Perl pattern matches and substitutions from your C program
-Our I<perl_eval()> lets us evaluate strings of Perl code, so we can
+The I<perl_eval_sv()> function lets us evaluate strings of Perl code, so we can
define some functions that use it to "specialize" in matches and
substitutions: I<match()>, I<substitute()>, and I<matches()>.
- char match(char *string, char *pattern);
+ I32 match(SV *string, char *pattern);
Given a string and a pattern (e.g., C<m/clasp/> or C</\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);
+ int substitute(SV **string, char *pattern);
-Given a pointer to a string and an C<=~> operation (e.g.,
+Given a pointer to an C<SV> and an C<=~> operation (e.g.,
C<s/bob/robert/g> or C<tr[A-Z][a-z]>), substitute() modifies the string
-according to the operation, returning the number of substitutions
+within the C<AV> at according to the operation, returning the number of substitutions
made.
- int matches(char *string, char *pattern, char **matches[]);
+ int matches(SV *string, char *pattern, AV **matches);
-Given a string, a pattern, and a pointer to an empty array of strings,
+Given an C<SV>, a pattern, and a pointer to an empty C<AV>,
matches() evaluates C<$string =~ $pattern> in an array context, and
-fills in I<matches> with the array elements (allocating memory as it
-does so), returning the number of matches found.
+fills in I<matches> with the array elements, returning the number of matches found.
Here's a sample program, I<match.c>, that uses all three (long lines have
been wrapped here):
- #include <EXTERN.h>
- #include <perl.h>
-
- static PerlInterpreter *my_perl;
- I32 perl_eval(char *string)
- {
- return perl_eval_sv(newSVpv(string,0), G_DISCARD);
- }
- /** match(string, pattern)
- **
- ** Used for matches in a scalar context.
- **
- ** Returns 1 if the match was successful; 0 otherwise.
- **/
- char match(char *string, char *pattern)
- {
- char *command;
- command = malloc(sizeof(char) * strlen(string) + strlen(pattern) + 37);
- sprintf(command, "$string = '%s'; $return = $string =~ %s",
- string, pattern);
- perl_eval(command);
- free(command);
- return SvIV(perl_get_sv("return", FALSE));
- }
- /** substitute(string, pattern)
- **
- ** Used for =~ operations that modify their left-hand side (s/// and tr///)
- **
- ** Returns the number of successful matches, and
- ** modifies the input string if there were any.
- **/
- int substitute(char *string[], char *pattern)
- {
- char *command;
- STRLEN length;
- command = malloc(sizeof(char) * strlen(*string) + strlen(pattern) + 35);
- sprintf(command, "$string = '%s'; $ret = ($string =~ %s)",
- *string, pattern);
- perl_eval(command);
- free(command);
- *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;
+ #include <EXTERN.h>
+ #include <perl.h>
+
+ /** my_perl_eval_sv(code, error_check)
+ ** kinda like perl_eval_sv(),
+ ** but we pop the return value off the stack
+ **/
+ SV* my_perl_eval_sv(SV *sv, I32 croak_on_error)
+ {
+ dSP;
+ SV* retval;
+ STRLEN n_a;
+
+ PUSHMARK(SP);
+ perl_eval_sv(sv, G_SCALAR);
+
+ SPAGAIN;
+ retval = POPs;
+ PUTBACK;
+
+ if (croak_on_error && SvTRUE(ERRSV))
+ croak(SvPVx(ERRSV, n_a));
+
+ return retval;
+ }
+
+ /** match(string, pattern)
+ **
+ ** Used for matches in a scalar context.
+ **
+ ** Returns 1 if the match was successful; 0 otherwise.
+ **/
+
+ I32 match(SV *string, char *pattern)
+ {
+ SV *command = NEWSV(1099, 0), *retval;
+ STRLEN n_a;
+
+ sv_setpvf(command, "my $string = '%s'; $string =~ %s",
+ SvPV(string,n_a), pattern);
+
+ retval = my_perl_eval_sv(command, TRUE);
+ SvREFCNT_dec(command);
+
+ return SvIV(retval);
+ }
+
+ /** substitute(string, pattern)
+ **
+ ** Used for =~ operations that modify their left-hand side (s/// and tr///)
+ **
+ ** Returns the number of successful matches, and
+ ** modifies the input string if there were any.
+ **/
+
+ I32 substitute(SV **string, char *pattern)
+ {
+ SV *command = NEWSV(1099, 0), *retval;
+ STRLEN n_a;
+
+ sv_setpvf(command, "$string = '%s'; ($string =~ %s)",
+ SvPV(*string,n_a), pattern);
+
+ retval = my_perl_eval_sv(command, TRUE);
+ SvREFCNT_dec(command);
+
+ *string = perl_get_sv("string", FALSE);
+ return SvIV(retval);
+ }
+
+ /** matches(string, pattern, matches)
+ **
+ ** Used for matches in an array context.
+ **
+ ** Returns the number of matches,
+ ** and fills in **matches with the matching substrings
+ **/
+
+ I32 matches(SV *string, char *pattern, AV **match_list)
+ {
+ SV *command = NEWSV(1099, 0);
I32 num_matches;
- STRLEN length;
- int i;
- command = malloc(sizeof(char) * strlen(string) + strlen(pattern) + 38);
- sprintf(command, "$string = '%s'; @array = ($string =~ %s)",
- string, pattern);
- perl_eval(command);
- free(command);
- 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);
- }
+ STRLEN n_a;
+
+ sv_setpvf(command, "my $string = '%s'; @array = ($string =~ %s)",
+ SvPV(string,n_a), pattern);
+
+ my_perl_eval_sv(command, TRUE);
+ SvREFCNT_dec(command);
+
+ *match_list = perl_get_av("array", FALSE);
+ num_matches = av_len(*match_list) + 1; /** assume $[ is 0 **/
+
return num_matches;
- }
- main (int argc, char **argv, char **env)
- {
+ }
+
+ main (int argc, char **argv, char **env)
+ {
+ PerlInterpreter *my_perl = perl_alloc();
char *embedding[] = { "", "-e", "0" };
- char *text, **match_list;
- int num_matches, i;
- int j;
- my_perl = perl_alloc();
- perl_construct( my_perl );
+ AV *match_list;
+ I32 num_matches, i;
+ SV *text = NEWSV(1099,0);
+ STRLEN n_a;
+
+ perl_construct(my_perl);
perl_parse(my_perl, NULL, 3, embedding, NULL);
- perl_run(my_perl);
-
- 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");
+
+ sv_setpv(text, "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 contains the word 'quarter'.\n\n");
else
- printf("match: Text doesn't contain 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 contains the word 'eighth'.\n\n");
else
- printf("match: Text doesn't contain 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]);
+ printf("match: %s\n", SvPV(*av_fetch(match_list, i, FALSE),n_a));
printf("\n");
- for (i = 0; i < num_matches; i++) {
- free(match_list[i]);
- }
- free(match_list);
+
/** Remove all vowels from text **/
num_matches = substitute(&text, "s/[aeiou]//gi");
if (num_matches) {
- printf("substitute: s/[aeiou]//gi...%d substitutions made.\n",
- num_matches);
- printf("Now text is: %s\n\n", text);
+ printf("substitute: s/[aeiou]//gi...%d substitutions made.\n",
+ num_matches);
+ printf("Now text is: %s\n\n", SvPV(text,n_a));
}
+
/** Attempt a substitution **/
if (!substitute(&text, "s/Perl/C/")) {
- printf("substitute: s/Perl/C...No substitution made.\n\n");
+ printf("substitute: s/Perl/C...No substitution made.\n\n");
}
- free(text);
+
+ SvREFCNT_dec(text);
+ PL_perl_destruct_level = 1;
perl_destruct(my_perl);
perl_free(my_perl);
- }
+ }
which produces the output (again, long lines have been wrapped here)
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,
+ 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
Once you've understood those, embedding Perl in C is easy.
-Because C has no built-in function for integer exponentiation, let's
+Because C has no builtin 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 I<pow()> function). First
I'll create a stub exponentiation function in I<power.pl>:
dSP; /* initialize stack pointer */
ENTER; /* everything created after here */
SAVETMPS; /* ...is a temporary variable. */
- PUSHMARK(sp); /* remember the stack pointer */
+ 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 */
int main (int argc, char **argv, char **env)
{
- char *my_argv[2];
+ char *my_argv[] = { "", "power.pl" };
my_perl = perl_alloc();
perl_construct( my_perl );
- my_argv[1] = (char *) malloc(10);
- sprintf(my_argv[1], "power.pl");
-
- perl_parse(my_perl, NULL, argc, my_argv, NULL);
+ perl_parse(my_perl, NULL, 2, my_argv, (char **)NULL);
perl_run(my_perl);
PerlPower(3, 4); /*** Compute 3 ** 4 ***/
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.
+memory once.
However, you have to be more cautious with namespace and variable
scoping when using a persistent interpreter. In previous examples
consumption is minimized. You'll also want to scope your variables
with L<perlfunc/my> whenever possible.
-
+
package Embed::Persistent;
#persistent.pl
-
+
use strict;
- use vars '%Cache';
-
+ our %Cache;
+ use Symbol qw(delete_package);
+
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 Safe.pm
- 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)
+ $Cache{$package}{mtime} <= $mtime)
{
- # we have compiled this subroutine already,
+ # we have compiled this subroutine already,
# it has not been updated on disk, nothing left to do
print STDERR "already compiled $package->handler\n";
}
local($/) = undef;
my $sub = <FH>;
close FH;
-
+
#wrap the code into a subroutine inside our unique package
my $eval = qq{package $package; sub handler { $sub; }};
{
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, $/;
}
-
+
1;
-
+
__END__
/* persistent.c */
- #include <EXTERN.h>
- #include <perl.h>
-
+ #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
#endif
-
+
static PerlInterpreter *perl = NULL;
-
+
int
main(int argc, char **argv, char **env)
{
char *args[] = { "", DO_CLEAN, NULL };
char filename [1024];
int exitstatus = 0;
-
+ STRLEN n_a;
+
if((perl = perl_alloc()) == NULL) {
fprintf(stderr, "no memory!");
exit(1);
}
- perl_construct(perl);
-
+ perl_construct(perl);
+
exitstatus = perl_parse(perl, NULL, 2, embedding, NULL);
-
- if(!exitstatus) {
+
+ 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;
- perl_call_argv("Embed::Persistent::eval_file",
+ perl_call_argv("Embed::Persistent::eval_file",
G_DISCARD | G_EVAL, args);
-
+
/* check $@ */
- if(SvTRUE(GvSV(errgv)))
- fprintf(stderr, "eval error: %s\n", SvPV(GvSV(errgv),na));
+ if(SvTRUE(ERRSV))
+ fprintf(stderr, "eval error: %s\n", SvPV(ERRSV,n_a));
}
}
-
- perl_destruct_level = 0;
- perl_destruct(perl);
- perl_free(perl);
+
+ PL_perl_destruct_level = 0;
+ perl_destruct(perl);
+ perl_free(perl);
exit(exitstatus);
}
-
Now compile:
- % cc -o persistent persistent.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+ % cc -o persistent persistent.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
Here's a example script file:
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.
+release any resources associated with the interpreter.
The program must take care to ensure that this takes place I<before>
the next interpreter is constructed. By default, the global variable
-C<perl_destruct_level> is set to C<0>, since extra cleaning isn't
+C<PL_perl_destruct_level> is set to C<0>, since extra cleaning isn't
needed when a program has only one interpreter.
-Setting C<perl_destruct_level> to C<1> makes everything squeaky clean:
+Setting C<PL_perl_destruct_level> to C<1> makes everything squeaky clean:
- perl_destruct_level = 1;
+ PL_perl_destruct_level = 1;
while(1) {
...
- /* reset global variables here with perl_destruct_level = 1 */
- perl_construct(my_perl);
+ /* reset global variables here with PL_perl_destruct_level = 1 */
+ perl_construct(my_perl);
...
/* clean and reset _everything_ during perl_destruct */
- perl_destruct(my_perl);
- perl_free(my_perl);
+ perl_destruct(my_perl);
+ perl_free(my_perl);
...
/* let's go do it again! */
}
-When I<perl_destruct()> is called, the interpreter's syntax parse tree
-and symbol tables are cleaned up, and global variables are reset.
+When I<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
C<-DMULTIPLICITY> flag when building Perl. By default, that sets
-C<perl_destruct_level> to C<1>.
+C<PL_perl_destruct_level> to C<1>.
Let's give it a try:
int main(int argc, char **argv, char **env)
{
- PerlInterpreter
+ PerlInterpreter
*one_perl = perl_alloc(),
- *two_perl = perl_alloc();
+ *two_perl = perl_alloc();
char *one_args[] = { "one_perl", SAY_HELLO };
char *two_args[] = { "two_perl", SAY_HELLO };
# define EXTERN_C extern
#endif
- static void xs_init _((void));
+ static void xs_init (void);
- EXTERN_C void boot_DynaLoader _((CV* cv));
- EXTERN_C void boot_Socket _((CV* cv));
+ EXTERN_C void boot_DynaLoader (CV* cv);
+ EXTERN_C void boot_Socket (CV* cv);
EXTERN_C void
Consult L<perlxs> and L<perlguts> for more details.
+=head1 Embedding Perl under Win32
+
+At the time of this writing (5.004), there are two versions of Perl
+which run under Win32. (The two versions are merging in 5.005.)
+Interfacing to ActiveState's Perl library is quite different from the
+examples in this documentation, as significant changes were made to
+the internal Perl API. However, it is possible to embed ActiveState's
+Perl runtime. For details, see the Perl for Win32 FAQ at
+http://www.perl.com/CPAN/doc/FAQs/win32/perlwin32faq.html.
+
+With the "official" Perl version 5.004 or higher, all the examples
+within this documentation will compile and run untouched, although
+the build process is slightly different between Unix and Win32.
+
+For starters, backticks don't work under the Win32 native command shell.
+The ExtUtils::Embed kit on CPAN ships with a script called
+B<genmake>, which generates a simple makefile to build a program from
+a single C source file. It can be used like this:
+
+ C:\ExtUtils-Embed\eg> perl genmake interp.c
+ C:\ExtUtils-Embed\eg> nmake
+ C:\ExtUtils-Embed\eg> interp -e "print qq{I'm embedded in Win32!\n}"
+
+You may wish to use a more robust environment such as the Microsoft
+Developer Studio. In this case, run this to generate perlxsi.c:
+
+ perl -MExtUtils::Embed -e xsinit
+
+Create a new project and Insert -> Files into Project: perlxsi.c,
+perl.lib, and your own source files, e.g. interp.c. Typically you'll
+find perl.lib in B<C:\perl\lib\CORE>, if not, you should see the
+B<CORE> directory relative to C<perl -V:archlib>. The studio will
+also need this path so it knows where to find Perl include files.
+This path can be added via the Tools -> Options -> Directories menu.
+Finally, select Build -> Build interp.exe and you're ready to go.
=head1 MORAL
=head1 AUTHOR
-Jon Orwant and <F<orwant@tpj.com>> and Doug MacEachern <F<dougm@osf.org>>,
-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 http://tpj.com.
+Jon Orwant <F<orwant@tpj.com>> and Doug MacEachern
+<F<dougm@osf.org>>, with small contributions from Tim Bunce, Tom
+Christiansen, Guy Decoux, Hallvard Furuseth, Dov Grobgeld, and Ilya
+Zakharevich.
-February 1, 1997
+Doug MacEachern has an article on embedding in Volume 1, Issue 4 of
+The Perl Journal (http://tpj.com). Doug is also the developer of the
+most widely-used Perl embedding: the mod_perl system
+(perl.apache.org), which embeds Perl in the Apache web server.
+Oracle, Binary Evolution, ActiveState, and Ben Sugars's nsapi_perl
+have used this model for Oracle, Netscape and Internet Information
+Server Perl plugins.
-Some of this material is excerpted from Jon Orwant's book: I<Perl 5
-Interactive>, Waite Group Press, 1996 (ISBN 1-57169-064-6) and appears
-courtesy of Waite Group Press.
+July 22, 1998
=head1 COPYRIGHT
-Copyright (C) 1995, 1996, 1997 Doug MacEachern and Jon Orwant. All
+Copyright (C) 1995, 1996, 1997, 1998 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.
+Permission is granted to make and distribute verbatim copies of this
+documentation provided the copyright notice and this permission notice are
+preserved on all copies.
+
+Permission is granted to copy and distribute modified versions of this
+documentation under the conditions for verbatim copying, provided also
+that they are marked clearly as modified versions, that the authors'
+names and title are unchanged (though subtitles and additional
+authors' names may be added), and that the entire resulting derived
+work is distributed under the terms of a permission notice identical
+to this one.
+
+Permission is granted to copy and distribute translations of this
+documentation into another language, under the above conditions for
+modified versions.
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