H2XS(1) H2XS(1)
NAME
h2xs - convert .h C header files to Perl extensions
SYNOPSIS
h2xs [-AOPXcdf] [-v version] [-n module_name] [-p prefix] [-s sub]
[headerfile [extra_libraries]]
h2xs -h
DESCRIPTION
h2xs builds a Perl extension from any C header file. The extension will
include functions which can be used to retrieve the value of any #define
statement which was in the C header.
The module_name will be used for the name of the extension. If
module_name is not supplied then the name of the header file will be
used, with the first character capitalized.
If the extension might need extra libraries, they should be included
here. The extension Makefile.PL will take care of checking whether the
libraries actually exist and how they should be loaded. The extra
libraries should be specified in the form -lm -lposix, etc, just as on
the cc command line. By default, the Makefile.PL will search through the
library path determined by Configure. That path can be augmented by
including arguments of the form -L/another/library/path in the extra-
libraries argument.
OPTIONS
-A Omit all autoload facilities. This is the same as -c but also
removes the require AutoLoader statement from the .pm file.
-F Additional flags to specify to C preprocessor when scanning header
for function declarations. Should not be used without -x.
-O Allows a pre-existing extension directory to be overwritten.
-P Omit the autogenerated stub POD section.
-X Omit the XS portion. Used to generate templates for a module which
is not XS-based.
-c Omit constant() from the .xs file and corresponding specialised
AUTOLOAD from the .pm file.
-d Turn on debugging messages.
-f Allows an extension to be created for a header even if that header
is not found in /usr/include.
-h Print the usage, help and version for this h2xs and exit.
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-n module_name
Specifies a name to be used for the extension, e.g., -n RPC::DCE
-p prefix
Specify a prefix which should be removed from the Perl function
names, e.g., -p sec_rgy_ This sets up the XS PREFIX keyword and
removes the prefix from functions that are autoloaded via the
constant() mechansim.
-s sub1,sub2
Create a perl subroutine for the specified macros rather than
autoload with the constant() subroutine. These macros are assumed
to have a return type of char *, e.g.,
-s sec_rgy_wildcard_name,sec_rgy_wildcard_sid.
-v version
Specify a version number for this extension. This version number is
added to the templates. The default is 0.01.
-x Automatically generate XSUBs basing on function declarations in the
header file. The package C::Scan should be installed. If this
option is specified, the name of the header file may look like
NAME1,NAME2. In this case NAME1 is used instead of the specified
string, but XSUBs are emitted only for the declarations included
from file NAME2.
Note that some types of arguments/return-values for functions may
result in XSUB-declarations/typemap-entries which need hand-editing.
Such may be objects which cannot be converted from/to a pointer
(like long long), pointers to functions, or arrays.
EXAMPLES
# Default behavior, extension is Rusers
h2xs rpcsvc/rusers
# Same, but extension is RUSERS
h2xs -n RUSERS rpcsvc/rusers
# Extension is rpcsvc::rusers. Still finds <rpcsvc/rusers.h>
h2xs rpcsvc::rusers
# Extension is ONC::RPC. Still finds <rpcsvc/rusers.h>
h2xs -n ONC::RPC rpcsvc/rusers
# Without constant() or AUTOLOAD
h2xs -c rpcsvc/rusers
# Creates templates for an extension named RPC
h2xs -cfn RPC
# Extension is ONC::RPC.
h2xs -cfn ONC::RPC
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# Makefile.PL will look for library -lrpc in
# additional directory /opt/net/lib
h2xs rpcsvc/rusers -L/opt/net/lib -lrpc
# Extension is DCE::rgynbase
# prefix "sec_rgy_" is dropped from perl function names
h2xs -n DCE::rgynbase -p sec_rgy_ dce/rgynbase
# Extension is DCE::rgynbase
# prefix "sec_rgy_" is dropped from perl function names
# subroutines are created for sec_rgy_wildcard_name and sec_rgy_wildcard_sid
h2xs -n DCE::rgynbase -p sec_rgy_ \
-s sec_rgy_wildcard_name,sec_rgy_wildcard_sid dce/rgynbase
# Make XS without defines in perl.h, but with function declarations
# visible from perl.h. Name of the extension is perl1.
# When scanning perl.h, define -DEXT=extern -DdEXT= -DINIT(x)=
# Extra backslashes below because the string is passed to shell.
# Note that a directory with perl header files would
# be added automatically to include path.
h2xs -xAn perl1 -F "-DEXT=extern -DdEXT= -DINIT\(x\)=" perl.h
# Same with function declaration in proto.h as visible from perl.h.
h2xs -xAn perl2 perl.h,proto.h
ENVIRONMENT
No environment variables are used.
AUTHOR
Larry Wall and others
SEE ALSO
the perl manpage, the perlxstut manpage, the ExtUtils::MakeMaker manpage,
and the AutoLoader manpage.
DIAGNOSTICS
The usual warnings if it cannot read or write the files involved.
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