XSUBPP

Section: Perl Programmers Reference Guide (1)
Updated: 2019-02-09
Page Index

NAME

xsubpp - compiler to convert Perl XS code into C code

SYNOPSIS

xsubpp [-v] [-except] [-s pattern] [-prototypes] [-noversioncheck] [-nolinenumbers] [-nooptimize] [-typemap typemap] [-output filename]... file.xs

DESCRIPTION

This compiler is typically run by the makefiles created by ExtUtils::MakeMaker or by Module::Build or other Perl module build tools.

xsubpp will compile XS code into C code by embedding the constructs necessary to let C functions manipulate Perl values and creates the glue necessary to let Perl access those functions. The compiler uses typemaps to determine how to map C function parameters and variables to Perl values.

The compiler will search for typemap files called typemap. It will use the following search path to find default typemaps, with the rightmost typemap taking precedence.

        ../../../typemap:../../typemap:../typemap:typemap

It will also use a default typemap installed as "ExtUtils::typemap".

OPTIONS

Note that the "XSOPT" MakeMaker option may be used to add these options to any makefiles generated by MakeMaker.

-hiertype

Retains '::' in type names so that C++ hierarchical types can be mapped.

-except

Adds exception handling stubs to the C code.

-typemap typemap

Indicates that a user-supplied typemap should take precedence over the default typemaps. This option may be used multiple times, with the last typemap having the highest precedence.

-output filename

Specifies the name of the output file to generate. If no file is specified, output will be written to standard output.

-v

Prints the xsubpp version number to standard output, then exits.

-prototypes

By default xsubpp will not automatically generate prototype code for all xsubs. This flag will enable prototypes.

-noversioncheck

Disables the run time test that determines if the object file (derived from the ".xs" file) and the ".pm" files have the same version number.

-nolinenumbers

Prevents the inclusion of '#line' directives in the output.

-nooptimize

Disables certain optimizations. The only optimization that is currently affected is the use of targets by the output C code (see perlguts). This may significantly slow down the generated code, but this is the way xsubpp of 5.005 and earlier operated.

-noinout

Disable recognition of "IN", "OUT_LIST" and "INOUT_LIST" declarations.

-noargtypes

Disable recognition of ANSI-like descriptions of function signature.

-C++

Currently doesn't do anything at all. This flag has been a no-op for many versions of perl, at least as far back as perl5.003_07. It's allowed here for backwards compatibility.

-s=... or -strip=...

This option is obscure and discouraged.

If specified, the given string will be stripped off from the beginning of the C function name in the generated XS functions (if it starts with that prefix). This only applies to XSUBs without "CODE" or "PPCODE" blocks. For example, the XS:

  void foo_bar(int i);

when "xsubpp" is invoked with "-s foo_" will install a "foo_bar" function in Perl, but really call bar(i) in C. Most of the time, this is the opposite of what you want and failure modes are somewhat obscure, so please avoid this option where possible.

ENVIRONMENT

No environment variables are used.

AUTHOR

Originally by Larry Wall. Turned into the "ExtUtils::ParseXS" module by Ken Williams.

MODIFICATION HISTORY

See the file Changes.