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APXS(8) apxs APXS(8)

NAME
apxs - APache eXtenSion tool

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

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

apxs -c [ -S name=value ] [ -o dsofile ] [ -I incdir ] [ -D name=value ] [ -L libdir ] [ -l libname ] [ -Wc,compiler-
flags ] [ -Wl,linker-flags ] files ...

apxs -i [ -S name=value ] [ -n modname ] [ -a ] [ -A ] dso-file ...

apxs -e [ -S name=value ] [ -n modname ] [ -a ] [ -A ] dso-file ...

SUMMARY
apxs 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 LoadModule directive from mod_so.

So to use this extension mechanism your platform has to support the DSO feature and your Apache httpd binary has to be
built with the mod_so module. The apxs tool automatically complains if this is not the case. You can check this yourself
by manually running the command

$ httpd -l

The module mod_so 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 apxs tool:

$ apxs -i -a -c mod_foo.c
gcc -fpic -DSHARED_MODULE -I/path/to/apache/include -c mod_foo.c
ld -Bshareable -o mod_foo.so mod_foo.o
cp mod_foo.so /path/to/apache/modules/mod_foo.so
chmod 755 /path/to/apache/modules/mod_foo.so
[activating module `foo' in /path/to/apache/etc/httpd.conf]
$ apachectl restart
/path/to/apache/sbin/apachectl restart: httpd not running, trying to start
[Tue Mar 31 11:27:55 1998] [debug] mod_so.c(303): loaded module foo_module
/path/to/apache/sbin/apachectl restart: httpd started
$ _

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 comâ
pile the object files.
...
DSO Compilation Options
-c This indicates the compilation operation. It first compiles the C source files (.c) of files into corresponding
object files (.o) and then builds a dynamically shared object in dsofile by linking these object files plus the
remaining object files (.o and .a) of files. If no -o option is specified the output file is guessed from the
first filename in files and thus usually defaults to mod_name.so.

...
DSO Installation and Configuration Options
-i This indicates the installation operation and installs one or more dynamically shared objects into the server's
modules directory.

-a This activates the module by automatically adding a corresponding LoadModule line to Apache's httpd.conf configuâ
ration file, or by enabling it if it already exists.