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Perl 5 version 8.9 documentation
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xsubpp - compiler to convert Perl XS code into C code


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


This compiler is typically run by the makefiles created by ExtUtils::MakeMaker.

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.

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

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


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.


No environment variables are used.


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


See the file Changes.


perl(1), perlxs(1), perlxstut(1), ExtUtils::ParseXS