Linker errors in a basic Apache module - c

Question

I am attempting to write a "hello world" module for Apache HTTPD 2.4. I'm receiving some linker errors when building the module, and many Google searches have not revealed a solution.
My questions are:
How can I resolve the ap_hook_handler linker error? I've searched through the Apache Portable Runtime source and headers and have not found it.
Why is there an undefined reference to main? I thought shared objects don't have a main() entry point.
The source code:
// Dependancies: apr-devel apr-util-devel
#include <httpd.h>
#include <http_config.h>
#include <apr_hooks.h>
static int test_handler(request_rec* request)
{
return OK;
}
static void register_hooks(apr_pool_t *pool)
{
ap_hook_handler(test_handler, NULL, NULL, APR_HOOK_LAST);
}
module AP_MODULE_DECLARE_DATA test_module =
{
STANDARD20_MODULE_STUFF,
NULL,
NULL,
NULL,
NULL,
NULL,
register_hooks
};
The build command:
apxs -lapr-1 -laprutil-1 -c test.c -o mod_test.so
The errors:
apxs -lapr-1 -laprutil-1 -c test.c -o mod_test.so
/usr/lib64/apr-1/build/libtool --silent --mode=compile gcc -prefer-pic -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -Wformat-security -fno-strict-aliasing -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -pthread -I/usr/include/httpd -I/usr/include/apr-1 -I/usr/include/apr-1 -c -o test.lo test.c && touch test.slo
/usr/lib64/apr-1/build/libtool --silent --mode=link gcc -o test.la -lapr-1 -laprutil-1 -rpath /usr/lib64/httpd/modules -module -avoid-version test.lo -o mod_test.so
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
.libs/test.o: In function `register_hooks':
/root/test/test.c:14: undefined reference to `ap_hook_handler'
collect2: ld returned 1 exit status
apxs:Error: Command failed with rc=65536

Answer 1

The order matters and the filenames have to go last:
apxs -c -o mod_test.so test.c
To install it automatically:
apxs -i -c -o mod_test.so -c test.c
This should work

Answer 2

As Ctx said, the order of parameters really matters. I use the following format of the APXS:
$APACHE/bin/apxs -c -a -i mod_test.c
what compiles, adds and installs the test module. It produces this output:
/usr/local/apr/build-1/libtool --silent --mode=compile gcc -prefer-pic -DLINUX -D_REENTRANT -D_GNU_SOURCE -g -O2 -pthread -I$APACHE_HOME/include -I/usr/local/apr/include/apr-1 -I/usr/local/apr/include/apr-1 -c -o mod_test.lo mod_test.c && touch mod_test.slo
/usr/local/apr/build-1/libtool --silent --mode=link gcc -o mod_test.la -rpath $APACHE_HOME/modules -module -avoid-version mod_test.lo
ar: `u' modifier ignored since `D' is the default (see `U')
$APACHE_HOME/build/instdso.sh SH_LIBTOOL='/usr/local/apr/build-1/libtool' mod_test.la $APACHE_HOME/modules
/usr/local/apr/build-1/libtool --mode=install install mod_test.la $APACHE_HOME/modules/
libtool: install: install .libs/mod_test.so $APACHE_HOME/modules/mod_test.so
libtool: install: install .libs/mod_test.lai $APACHE_HOME/modules/mod_test.la
libtool: install: install .libs/mod_test.a $APACHE_HOME/modules/mod_test.a
libtool: install: chmod 644 $APACHE_HOME/modules/mod_test.a
libtool: install: ranlib $APACHE_HOME/modules/mod_test.a
libtool: finish:
----------------------------------------------------------------------
Libraries have been installed in:
$APACHE_HOME/modules
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,-rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.
----------------------------------------------------------------------
chmod 755 $APACHE_HOME/modules/mod_test.so
[activating module `test' in $APACHE_HOME/conf/httpd.conf]
By providing the -o option you can get rid of undefined reference to main error message.