apxs - APache eXtenSion tool

is a tool for building and installing extension modules for the Apache HyperText Transfer Protocol (HTTP) server. This is achieved by building a dynamic shared object (DSO) from one or more source or object files which then can be loaded into the Apache server under runtime via the

So to use this extension mechanism your platform has to support the DSO feature and your Apache

binary has to be built with the httpd

tool automatically complains if this is not the case. You can check this yourself by manually running the command

should be part of the displayed list. If these requirements are fulfilled you can easily extend your Apache server's functionality by installing your own modules with the DSO mechanism by the help of this mod_soapxs

$ apxs -i -a -c mod_foo.c

gcc -fpic -DSHAREDMODULE -I/path/to/apache/include -c modfoo.c

ld -Bshareable -o modfoo.so modfoo.o

[activating module `foo' in /path/to/apache/etc/apache2.conf]

/path/to/apache/sbin/apache2ctl restart: httpd not running, trying to start

[Tue Mar 31 11:27:55 1998] [debug] modso.c(303): loaded module foomodule

The arguments files can be any C source file (.c), a object file (.o) or even a library archive (.a). The apxs

tool automatically recognizes these extensions and automatically used the C source files for compilation while just using the object and archive files for the linking phase. But when using such pre-compiled objects make sure they are compiled for position independent code (PIC) to be able to use them for a dynamically loaded shared object. For instance with GCC you always just have to use -fpic

. For other C compilers consult its manual page or at watch for the flags apxs

uses to compile the object files.

For more details about DSO support in Apache read the documentation of

or perhaps even read the modsosrc/modules/standard/modso.c

apxs -g [ -S name=value ] -n modname

apxs -q [ -v ] [ -S name=value ] query ...

(template generation) option. Use this to explicitly specify the module name. For option -g

tool tries to determine the name from the source or (as a fallback) at least by guessing it from the filename.-q

. When invoked without -v

parameter formats the list output. Use this to manually determine settings used to build the httpd

that will load your module. For instance use

INC=-Iapxs -q INCLUDEDIR

inside your own Makefiles if you need manual access to Apache's C header files.

) and there two files: A sample module source file named mod_name.c

which can be used as a template for creating your own modules or as a quick start for playing with the apxs mechanism. And a corresponding Makefile

option is specified the output file is guessed from the first filename in mod_name.so

command. Use this to add local compiler-specific options.-Wl,linker-flags

configuration file, or by enabling it if it already exists.-A

but the created LoadModule

directive is prefixed with a hash sign (#

operation to edit Apache's apache2.conf

configuration file without attempting to install the module.Assume you have an Apache module named mod_foo.c

available which should extend Apache's server functionality. To accomplish this you first have to compile the C source into a shared object suitable for loading into the Apache server under runtime via the following command:

/path/to/libtool --mode=compile gcc ... -c mod_foo.c

Then you have to update the Apache configuration by making sure a

directive is present to load this shared object. To simplify this step LoadModuleapxs

provides an automatic way to install the shared object in its "modules" directory and updating the apache2.conf

is added to the configuration file if still not present. If you want to have this disabled per default use the -A

For a quick test of the apxs mechanism you can create a sample Apache module template plus a corresponding Makefile via:

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