NAME

AutoCons::HOWTO::C - HOWTO write a Construct.PL for a C program

DESCRIPTION

AutoCons is a cons Construct generator similar to ExtUtils::MakeMaker or Gnu Autoconf, except that cons is far more portable than make. For the developer, this means that your program will build on any system that cons will. For a user, this means that you don't need a "make" program to build your program.

This HOWTO describes how to write a Construct.PL to build C programs.

INSTALL

Modules are installed with a simple group of commands.

 perl Construct.PL
 cons
 cons -- test
 cons -- install

Adding targets

In order to build a C program, you have to add new targets that match up to your source. For example, to build the simple Hello World!:

 Use AutoCons;
 WriteCS(
   Name => "Hello World!",
   Version => "1",
 );
 Targ("Program","blib/hello","hello.c");

"Why is the hello executable stored in blib?" Well, when AutoCons configures the Construct, it sets it up to build the blib directory by default (when the user runs cons.) So by storing the output (hello) in blib, you tell cons to build it by default.

Other types of targets are available too.

 Use AutoCons;
 WriteCS(
   Name => "Hello World!",
   Version => "1",
 );
 Targ("Program","blib/bin/hello","[ hello.c, blib/lib/libworld ]");
 Targ("Library","blib/lib/libworld","libworld.c");

Your program also needs to be installed.

 Use AutoCons;
 WriteCS(
   Name => "Hello World!",
   Version => "1",
 );
 Targ("Program","blib/bin/hello","[ hello.c, blib/lib/libworld ]");  
 Targ("Install","$installbin","blib/bin/hello");
 Targ("Library","blib/lib/libworld","libworld.c");
 Targ("Install","$installlib","blib/lib/libworld");

For a full list of target types, see "Default construction methods" in cons.

Config.h

It is also possible to find system-dependent information. This is done by creating a Config.h.PL.

This file will load AutoCons::ConfigH as opposed to the regular AutoCons. The Config.h file it generates will contain ALL of the info contained in Config.pm (a database of system-dependent information from perl with over 900 values) as well as any information you add to it. See Config for more info. A basic Config.h.PL would look like this.

 use AutoCons::ConfigH;
 ConfigH();

A more advanced one like this.

 use AutoCons::ConfigH;
 use ExtUtils::PkgConfig;
 %pkg_info = ExtUtils::PkgConfig->find (Gtk+);
 
 ConfigH("
   #define Gtklibs $pkg_info{libs}
   #define Gtkflags $pkg_info{cflags}
   #define Gtkver $pkg_info{modversion}
 ");

I'll explain it bit-by-bit.

 use ExtUtils::PkgConfig

ExtUtils::PkgConfig is a wrapper around pkg-config that makes it easy to use.

 %pkg_info = ExtUtils::PkgConfig->find (Gtk+);

...grabs info about Gtk+ and stores it.

 #define ... $pkg_info{...}

...uses that info.

You probably also want to link against your library.

 # Construct.PL
 use AutoCons;
 use ExtUtils::PkgConfig;
 %Gtk = ExtUtils::PkgConfig->find (gtk+);
 WriteCS(
   Name => "foo",
   Version => 1,
   Libs => $Gtk{libs}
 );

SEE ALSO

Other HOWTOs: AutoCons::HOWTO(1) AutoCons::HOWTO::Perl(1)

Other: AutoCons(3) cons(1) perl(1)

cpanm AutoCons

perl -MCPAN -e shell
install AutoCons