From: Gurusamy Sarathy Date: Wed, 22 Jul 1998 18:13:31 +0000 (+0000) Subject: newer perlembed.pod X-Git-Tag: perl-5.005~4 X-Git-Url: https://perl5.git.perl.org/perl5.git/commitdiff_plain/e010571f6cb51179682ace9243bd94062586abdf newer perlembed.pod p4raw-id: //depot/perl@1644 --- diff --git a/pod/perlembed.pod b/pod/perlembed.pod index f7c8e4a..2aadeff 100644 --- a/pod/perlembed.pod +++ b/pod/perlembed.pod @@ -12,7 +12,7 @@ Do you want to: =item B -Read L, L and L. +Read L, L, L, and L. =item B @@ -20,7 +20,8 @@ Read about back-quotes and about C and C in L. =item B -Read about do(), eval(), require(), and use() in L. +Read about L and L and L +and L. =item B @@ -34,49 +35,27 @@ Read on... =head2 ROADMAP -Compiling your C program +L -There's one example in each of the nine sections: +L -=over 4 +L -=item * +L -Adding a Perl interpreter to your C program +L -=item * +L -Calling a Perl subroutine from your C program +L -=item * +L -Evaluating a Perl statement from your C program +L -=item * +L -Performing Perl pattern matches and substitutions from your C program - -=item * - -Fiddling with the Perl stack from your C program - -=item * - -Maintaining a persistent interpreter - -=item * - -Maintaining multiple interpreter instances - -=item * - -Using Perl modules, which themselves use C libraries, from your C program - -=item * - -Embedding Perl under Win32 - -=back +=back =head2 Compiling your C program @@ -117,15 +96,15 @@ 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: +L, 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 5.003_05, 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 @@ -172,7 +151,7 @@ information you may find useful. In a sense, perl (the C program) is a good example of embedding Perl (the language), so I'll demonstrate embedding with I, -from the source distribution. Here's a bastardized, nonportable +included in the source distribution. Here's a bastardized, nonportable version of I containing the essentials of embedding: #include /* from the Perl distribution */ @@ -215,13 +194,13 @@ or 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 before -calling I. +calling I. =head2 Calling a Perl subroutine from your C program To call individual Perl subroutines, you can use any of the B functions documented in L. -In this example we'll use perl_call_argv(). +In this example we'll use C. That's shown below, in a program I'll call I. @@ -278,20 +257,21 @@ If you want to pass arguments to the Perl subroutine, you can add strings to the C-terminated C list passed to I. 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. +last section of this document: L. =head2 Evaluating a Perl statement from your C program Perl provides two API functions to evaluate pieces of Perl code. -These are perl_eval_sv() and perl_eval_pv(). +These are L and L. 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 -use(), require(), and do() to include external Perl files. +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, L, and L to +include external Perl files. -perl_eval_pv() lets us evaluate individual Perl strings, and then +I lets us evaluate individual Perl strings, and then extract variables for coercion into C types. The following program, I, executes three Perl strings, extracting an C from the first, a C from the second, and a C from the third. @@ -340,7 +320,7 @@ I to create a string: 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 perl_eval_pv() instead. Example: +from I instead. Example: ... SV *val = perl_eval_pv("reverse 'rekcaH lreP rehtonA tsuJ'", TRUE); @@ -352,11 +332,11 @@ variables and we've simplified our code as well. =head2 Performing Perl pattern matches and substitutions from your C program -The I function lets us evaluate chunks of Perl code, so we can +The I function lets us evaluate strings of Perl code, so we can define some functions that use it to "specialize" in matches and substitutions: I, I, and I. - char match(SV *string, char *pattern); + I32 match(SV *string, char *pattern); Given a string and a pattern (e.g., C or C, which in your C program might appear as "/\\b\\w*\\b/"), match() @@ -646,10 +626,10 @@ 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 +the code into that package using L. 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 +after it's no longer needed. Using L, We'll call the subroutine C which lives in the file C and pass the filename and boolean cleanup/cache flag as arguments. @@ -660,7 +640,7 @@ 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. +with L whenever possible. package Embed::Persistent; @@ -967,39 +947,39 @@ Consult L and L for more details. =head1 Embedding Perl under Win32 -At the time of this writing, there are two versions of Perl which run -under Win32. Interfacing to Activeware'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 Activeware's Perl runtime, see the Perl for Win32 FAQ: -http://www.perl.com/perl/faq/win32/Perl_for_Win32_FAQ.html +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/perl/faq/win32/Perl_for_Win32_FAQ.html. With the "official" Perl version 5.004 or higher, all the examples -within this documentation will compile and run untouched, although, +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! +For starters, backticks don't work under the Win32 native command shell. The ExtUtils::Embed kit on CPAN ships with a script called B, which generates a simple makefile to build a program from -a single C source file. It can be used like so: +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 MS Developer -stdio. In this case, to generate perlxsi.c run: +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, 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, if not, you should see the B -directory relative to C. -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. Finnally, select Build -> Build interp.exe and -you're ready to go! +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, if not, you should see the +B directory relative to C. 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 @@ -1010,28 +990,38 @@ each from the other, combine them as you wish. =head1 AUTHOR -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 http://tpj.com. +Jon Orwant > and Doug MacEachern +>, with small contributions from Tim Bunce, Tom +Christiansen, Guy Decoux, Hallvard Furuseth, Dov Grobgeld, and Ilya +Zakharevich. -July 17, 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, 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.