=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?>
Embedding Perl under Win32
-=back
+=back
=head2 Compiling your C program
perl -MConfig -e 'print $Config{archlib}'
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:
+L</Adding a Perl interpreter to your C program>, on my Linux box:
% 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
-o interp interp.c -lperl -lm
-(That's all one line.) On my DEC Alpha running old 5.003_05, the
+(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
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>,
-included in the source distribution. Here's a bastardized, nonportable
+included in the source distribution. Here's a bastardized, non-portable
version of I<miniperlmain.c> containing the essentials of embedding:
- #include <EXTERN.h> /* from the Perl distribution */
-
#include <perl.h> /* from the Perl distribution */
+ #include <EXTERN.h> /* from the Perl distribution */
+ #include <perl.h> /* from the Perl distribution */
- static PerlInterpreter *my_perl; /*** The Perl interpreter ***/
+ static PerlInterpreter *my_perl; /*** The Perl interpreter ***/
- int main(int argc, char **argv, char **env)
- {
+ int main(int argc, char **argv, char **env)
+ {
PERL_SYS_INIT3(&argc,&argv,&env);
my_perl = perl_alloc();
perl_construct(my_perl);
perl_destruct(my_perl);
perl_free(my_perl);
PERL_SYS_TERM();
- }
+ }
Notice that we don't use the C<env> pointer. Normally handed to
C<perl_parse> as its final argument, C<env> here is replaced by
-C<NULL>, which means that the current environment will be used. The macros
-PERL_SYS_INIT3() and PERL_SYS_TERM() provide system-specific tune up
-of the C runtime environment necessary to run Perl interpreters; since
-PERL_SYS_INIT3() may change C<env>, it may be more appropriate to provide
-C<env> as an argument to perl_parse().
+C<NULL>, which means that the current environment will be used.
+
+The macros PERL_SYS_INIT3() and PERL_SYS_TERM() provide system-specific
+tune up of the C runtime environment necessary to run Perl interpreters;
+they should only be called once regardless of how many interpreters you
+create or destroy. Call PERL_SYS_INIT3() before you create your first
+interpreter, and PERL_SYS_TERM() after you free your last interpreter.
+
+Since PERL_SYS_INIT3() may change C<env>, it may be more appropriate to
+provide C<env> as an argument to perl_parse().
+
+Also notice that no matter what arguments you pass to perl_parse(),
+PERL_SYS_INIT3() must be invoked on the C main() argc, argv and env and
+only once.
+
+Mind that argv[argc] must be NULL, same as those passed to a main
+function in C.
Now compile this program (I'll call it I<interp.c>) into an executable:
I'll define the I<showtime> subroutine in a file called I<showtime.pl>:
- print "I shan't be printed.";
+ print "I shan't be printed.";
- sub showtime {
- print time;
- }
-
-Simple enough. Now compile and run:
+ sub showtime {
+ print time;
+ }
- % cc -o showtime showtime.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+Simple enough. Now compile and run:
- % showtime showtime.pl
- 818284590
+ % cc -o showtime showtime.c \
+ `perl -MExtUtils::Embed -e ccopts -e ldopts`
+ % showtime showtime.pl
+ 818284590
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 I<perl_run>, as we set
+In this particular case we don't have to call I<perl_run>, as we set
the PL_exit_flag PERL_EXIT_DESTRUCT_END which executes END blocks in
perl_destruct.
strings to the C<NULL>-terminated C<args> list passed to
I<call_argv>. For other data types, or to examine return values,
you'll need to manipulate the Perl stack. That's demonstrated in
-L<Fiddling with the Perl stack from your C program>.
+L</Fiddling with the Perl stack from your C program>.
=head2 Evaluating a Perl statement from your C 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 <EXTERN.h>
+ #include <perl.h>
- static PerlInterpreter *my_perl;
+ static PerlInterpreter *my_perl;
- main (int argc, char **argv, char **env)
- {
- STRLEN n_a;
- char *embedding[] = { "", "-e", "0" };
+ main (int argc, char **argv, char **env)
+ {
+ char *embedding[] = { "", "-e", "0" };
- PERL_SYS_INIT3(&argc,&argv,&env);
- my_perl = perl_alloc();
- perl_construct( my_perl );
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ my_perl = perl_alloc();
+ perl_construct( my_perl );
- perl_parse(my_perl, NULL, 3, embedding, NULL);
- PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
- perl_run(my_perl);
+ perl_parse(my_perl, NULL, 3, embedding, NULL);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+ 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 $a as an integer **/
+ eval_pv("$a = 3; $a **= 2", TRUE);
+ printf("a = %d\n", SvIV(get_sv("a", 0)));
- /** Treat $a as a float **/
- eval_pv("$a = 3.14; $a **= 2", TRUE);
- printf("a = %f\n", SvNV(get_sv("a", FALSE)));
+ /** Treat $a as a float **/
+ eval_pv("$a = 3.14; $a **= 2", TRUE);
+ printf("a = %f\n", SvNV(get_sv("a", 0)));
- /** Treat $a as a string **/
- eval_pv("$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a);", TRUE);
- printf("a = %s\n", SvPV(get_sv("a", FALSE), n_a));
+ /** Treat $a as a string **/
+ eval_pv(
+ "$a = 'rekcaH lreP rehtonA tsuJ'; $a = reverse($a);", TRUE);
+ printf("a = %s\n", SvPV_nolen(get_sv("a", 0)));
- perl_destruct(my_perl);
- perl_free(my_perl);
- PERL_SYS_TERM();
- }
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ }
-All of those strange functions with I<sv> in their names help convert Perl scalars to C types. They're described in L<perlguts> and L<perlapi>.
+All of those strange functions with I<sv> in their names help convert Perl
+scalars to C types. They're described in L<perlguts> and L<perlapi>.
If you compile and run I<string.c>, you'll see the results of using
I<SvIV()> to create an C<int>, I<SvNV()> to create a C<float>, and
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
+store the computed value of our eval'ed expression. It is also
possible and in most cases a better strategy to fetch the return value
from I<eval_pv()> instead. Example:
...
- STRLEN n_a;
SV *val = eval_pv("reverse 'rekcaH lreP rehtonA tsuJ'", TRUE);
- printf("%s\n", SvPV(val,n_a));
+ printf("%s\n", SvPV_nolen(val));
...
This way, we avoid namespace pollution by not creating global
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
-within the C<SV> as according to the operation, returning the number of substitutions
-made.
+within the C<SV> as according to the operation, returning the number of
+substitutions made.
- int matches(SV *string, char *pattern, AV **matches);
+ SSize_t matches(SV *string, char *pattern, AV **matches);
Given an C<SV>, a pattern, and a pointer to an empty C<AV>,
matches() evaluates C<$string =~ $pattern> in a list context, and
-fills in I<matches> with the array elements, 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):
static PerlInterpreter *my_perl;
/** my_eval_sv(code, error_check)
- ** kinda like eval_sv(),
- ** but we pop the return value off the stack
+ ** kinda like eval_sv(),
+ ** but we pop the return value off the stack
**/
SV* my_eval_sv(SV *sv, I32 croak_on_error)
{
dSP;
SV* retval;
- STRLEN n_a;
+
PUSHMARK(SP);
eval_sv(sv, G_SCALAR);
PUTBACK;
if (croak_on_error && SvTRUE(ERRSV))
- croak(SvPVx(ERRSV, n_a));
+ croak(SvPVx_nolen(ERRSV));
return retval;
}
I32 match(SV *string, char *pattern)
{
- SV *command = NEWSV(1099, 0), *retval;
- STRLEN n_a;
+ SV *command = newSV(0), *retval;
sv_setpvf(command, "my $string = '%s'; $string =~ %s",
- SvPV(string,n_a), pattern);
+ SvPV_nolen(string), pattern);
retval = my_eval_sv(command, TRUE);
SvREFCNT_dec(command);
/** substitute(string, pattern)
**
- ** Used for =~ operations that modify their left-hand side (s/// and tr///)
+ ** Used for =~ operations that
+ ** modify their left-hand side (s/// and tr///)
**
** Returns the number of successful matches, and
** modifies the input string if there were any.
I32 substitute(SV **string, char *pattern)
{
- SV *command = NEWSV(1099, 0), *retval;
- STRLEN n_a;
+ SV *command = newSV(0), *retval;
sv_setpvf(command, "$string = '%s'; ($string =~ %s)",
- SvPV(*string,n_a), pattern);
+ SvPV_nolen(*string), pattern);
retval = my_eval_sv(command, TRUE);
SvREFCNT_dec(command);
- *string = get_sv("string", FALSE);
+ *string = get_sv("string", 0);
return SvIV(retval);
}
** and fills in **matches with the matching substrings
**/
- I32 matches(SV *string, char *pattern, AV **match_list)
+ SSize_t matches(SV *string, char *pattern, AV **match_list)
{
- SV *command = NEWSV(1099, 0);
- I32 num_matches;
- STRLEN n_a;
+ SV *command = newSV(0);
+ SSize_t num_matches;
sv_setpvf(command, "my $string = '%s'; @array = ($string =~ %s)",
- SvPV(string,n_a), pattern);
+ SvPV_nolen(string), pattern);
my_eval_sv(command, TRUE);
SvREFCNT_dec(command);
- *match_list = get_av("array", FALSE);
- num_matches = av_len(*match_list) + 1; /** assume $[ is 0 **/
+ *match_list = get_av("array", 0);
+ num_matches = av_top_index(*match_list) + 1;
return num_matches;
}
AV *match_list;
I32 num_matches, i;
SV *text;
- STRLEN n_a;
PERL_SYS_INIT3(&argc,&argv,&env);
my_perl = perl_alloc();
perl_parse(my_perl, NULL, 3, embedding, NULL);
PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
- text = NEWSV(1099,0);
- 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");
+ text = newSV(0);
+ 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("matches: m/(wi..)/g found %d matches...\n", num_matches);
for (i = 0; i < num_matches; i++)
- printf("match: %s\n", SvPV(*av_fetch(match_list, i, FALSE),n_a));
+ printf("match: %s\n",
+ SvPV_nolen(*av_fetch(match_list, i, FALSE)));
printf("\n");
/** 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", SvPV(text,n_a));
+ printf("substitute: s/[aeiou]//gi...%lu substitutions made.\n",
+ (unsigned long)num_matches);
+ printf("Now text is: %s\n\n", SvPV_nolen(text));
}
/** Attempt a substitution **/
which produces the output (again, long lines have been wrapped here)
- match: Text contains the word 'quarter'.
+ match: Text contains the word 'quarter'.
- match: Text doesn't contain the word 'eighth'.
+ match: Text doesn't contain the word 'eighth'.
- matches: m/(wi..)/g found 2 matches...
- match: will
- match: with
+ 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/[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.
+ substitute: s/Perl/C...No substitution made.
=head2 Fiddling with the Perl stack from your C program
two arguments into I<expo()> and to pop the return value out. Take a
deep breath...
- #include <EXTERN.h>
+ #include <EXTERN.h>
+ #include <perl.h>
- static PerlInterpreter *my_perl;
+ static PerlInterpreter *my_perl;
- static void
- PerlPower(int a, int b)
- {
- dSP; /* initialize stack pointer */
- ENTER; /* everything created after here */
- SAVETMPS; /* ...is 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 */
- 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);
- PUTBACK;
- FREETMPS; /* free that return value */
- LEAVE; /* ...and the XPUSHed "mortal" args.*/
- }
+ static void
+ PerlPower(int a, int b)
+ {
+ dSP; /* initialize stack pointer */
+ ENTER; /* everything created after here */
+ SAVETMPS; /* ...is 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 */
+ 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);
+ PUTBACK;
+ FREETMPS; /* free that return value */
+ LEAVE; /* ...and the XPUSHed "mortal" args.*/
+ }
- int main (int argc, char **argv, char **env)
- {
- char *my_argv[] = { "", "power.pl" };
+ int main (int argc, char **argv, char **env)
+ {
+ char *my_argv[] = { "", "power.pl" };
- PERL_SYS_INIT3(&argc,&argv,&env);
- my_perl = perl_alloc();
- perl_construct( my_perl );
+ PERL_SYS_INIT3(&argc,&argv,&env);
+ my_perl = perl_alloc();
+ perl_construct( my_perl );
- perl_parse(my_perl, NULL, 2, my_argv, (char **)NULL);
- PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
- perl_run(my_perl);
+ perl_parse(my_perl, NULL, 2, my_argv, (char **)NULL);
+ PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+ perl_run(my_perl);
- PerlPower(3, 4); /*** Compute 3 ** 4 ***/
+ PerlPower(3, 4); /*** Compute 3 ** 4 ***/
- perl_destruct(my_perl);
- perl_free(my_perl);
- PERL_SYS_TERM();
- }
+ perl_destruct(my_perl);
+ perl_free(my_perl);
+ PERL_SYS_TERM();
+ }
#include <EXTERN.h>
#include <perl.h>
- /* 1 = clean out filename's symbol table after each request, 0 = don't */
+ /* 1 = clean out filename's symbol table after each request,
+ 0 = don't
+ */
#ifndef DO_CLEAN
#define DO_CLEAN 0
#endif
char *args[] = { "", DO_CLEAN, NULL };
char filename[BUFFER_SIZE];
int exitstatus = 0;
- STRLEN n_a;
PERL_SYS_INIT3(&argc,&argv,&env);
if((my_perl = perl_alloc()) == NULL) {
}
perl_construct(my_perl);
+ PL_origalen = 1; /* don't let $0 assignment update the
+ proctitle or embedding[0] */
exitstatus = perl_parse(my_perl, NULL, 2, embedding, NULL);
PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
if(!exitstatus) {
fgets(filename, BUFFER_SIZE, stdin)) {
filename[strlen(filename)-1] = '\0'; /* strip \n */
- /* call the subroutine, passing it the filename as an argument */
+ /* call the subroutine,
+ passing it the filename as an argument */
args[0] = filename;
call_argv("Embed::Persistent::eval_file",
G_DISCARD | G_EVAL, args);
/* check $@ */
if(SvTRUE(ERRSV))
- fprintf(stderr, "eval error: %s\n", SvPV(ERRSV,n_a));
+ fprintf(stderr, "eval error: %s\n", SvPV_nolen(ERRSV));
}
}
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 an example script file:
to get the new behaviour. This also enables the running of END blocks if
the perl_parse fails and C<perl_destruct> will return the exit value.
+=head2 $0 assignments
+
+When a perl script assigns a value to $0 then the perl runtime will
+try to make this value show up as the program name reported by "ps" by
+updating the memory pointed to by the argv passed to perl_parse() and
+also calling API functions like setproctitle() where available. This
+behaviour might not be appropriate when embedding perl and can be
+disabled by assigning the value C<1> to the variable C<PL_origalen>
+before perl_parse() is called.
+
+The F<persistent.c> example above is for instance likely to segfault
+when $0 is assigned to if the C<PL_origalen = 1;> assignment is
+removed. This because perl will try to write to the read only memory
+of the C<embedding[]> strings.
+
=head2 Maintaining multiple interpreter instances
Some rare applications will need to create more than one interpreter
not be initialized correctly between consecutive runs and your
application may crash.
+See also L<perlxs/Thread-aware system interfaces>.
+
Using C<-Dusethreads -Duseithreads> rather than C<-Dusemultiplicity>
is more appropriate if you intend to run multiple interpreters
concurrently in different threads, because it enables support for
#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)"
Compile as usual:
- % cc -o multiplicity multiplicity.c `perl -MExtUtils::Embed -e ccopts -e ldopts`
+ % cc -o multiplicity multiplicity.c \
+ `perl -MExtUtils::Embed -e ccopts -e ldopts`
Run it, Run it:
Hi, I'm one_perl
Hi, I'm two_perl
-=head2 Using Perl modules, which themselves use C libraries, from your C program
+=head2 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 I<use()>s a Perl module (such as I<Socket>) which itself uses a C or C++ library,
-this probably happened:
+that I<use()>s a Perl module (such as I<Socket>) which itself uses a C or C++
+library, this probably happened:
Can't load module Socket, dynamic loading not available in this perl.
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 I<perlmain.c>
-to see how Perl does this:
+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
+I<perlmain.c> to see how Perl does this:
static void xs_init (pTHX);
Consult L<perlxs>, L<perlguts>, and L<perlapi> for more details.
-=head1 Embedding Perl under Win32
-
-In general, all of the source code shown here should work unmodified under
-Windows.
-
-However, there are some caveats about the command-line examples shown.
-For starters, backticks won'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.
+=head2 Using embedded Perl with POSIX locales
+
+(See L<perllocale> for information about these.)
+When a Perl interpreter normally starts up, it tells the system it wants
+to use the system's default locale. This is often, but not necessarily,
+the "C" or "POSIX" locale. Absent a S<C<"use locale">> within the perl
+code, this mostly has no effect (but see L<perllocale/Not within the
+scope of "use locale">). Also, there is not a problem if the
+locale you want to use in your embedded Perl is the same as the system
+default. However, this doesn't work if you have set up and want to use
+a locale that isn't the system default one. Starting in Perl v5.20, you
+can tell the embedded Perl interpreter that the locale is already
+properly set up, and to skip doing its own normal initialization. It
+skips if the environment variable C<PERL_SKIP_LOCALE_INIT> is set (even
+if set to 0 or C<"">). A Perl that has this capability will define the
+C pre-processor symbol C<HAS_SKIP_LOCALE_INIT>. This allows code that
+has to work with multiple Perl versions to do some sort of work-around
+when confronted with an earlier Perl.
=head1 Hiding Perl_
-If you completely hide the short forms forms of the Perl public API,
+If you completely hide the short forms of the Perl public API,
add -DPERL_NO_SHORT_NAMES to the compilation flags. This means that
for example instead of writing
Perl_warn(aTHX_ "%d bottles of beer on the wall", bottlecount);
-(See L<perlguts/Background and PERL_IMPLICIT_CONTEXT for the explanation
-of the C<aTHX_>.> ) Hiding the short forms is very useful for avoiding
+(See L<perlguts/"Background and PERL_IMPLICIT_CONTEXT"> for the explanation
+of the C<aTHX_>. ) Hiding the short forms is very useful for avoiding
all sorts of nasty (C preprocessor or otherwise) conflicts with other
software packages (Perl defines about 2400 APIs with these short names,
take or leave few hundred, so there certainly is room for conflict.)
have used this model for Oracle, Netscape and Internet Information
Server Perl plugins.
-July 22, 1998
-
=head1 COPYRIGHT
Copyright (C) 1995, 1996, 1997, 1998 Doug MacEachern and Jon Orwant. All
Rights Reserved.
-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.
+This document may be distributed under the same terms as Perl itself.
https://perl5.git.perl.org / perl5.git / blobdiff