Apache HTTP Server Version 1.3

Module mod_dll

This module is contained in the mod_dll.c file, and is compiled in by default for Windows. It provides for loading of executable code and modules into the server at start-up time, when they are contained in Win32 DLLs.

Summary

The DLL module loads other modules into the server as it is configuring itself (the first time only, rereading the config files cannot affect the state of loaded modules), when these modules are compiled into DLL files.

This module is included with Apache 1.3 and later, and is available only when using Microsoft Windows.

Creating DLL Modules

The Apache module API is unchanged between the Unix and Windows versions. Many modules will run on Windows with no or little change from Unix, although others rely on aspects of the Unix architecture which are not present in Windows, and will not work.

When a module does work, it can be added to the server in one of two ways. As with Unix, it can be compiled into the server. Because Apache for Windows does not have the Configure program of Apache for Unix, the module's source file must be added to the ApacheCore project file, and its symbols must be added to the nt\modules.c file.

The second way is to compile the module as a DLL, a shared library that can be loaded into the server at runtime, using the LoadModule directive. These module DLLs can be distributed and run on any Apache for Windows installation, without recompilation of the server.

To create a module DLL, a small change is necessary to the module's source file: The module record must be exported from the DLL (which will be created later; see below). To do this, add the MODULE_VAR_EXPORT (defined in the Apache header files) to your module's module record definition. For example, if your module has:

    module foo_module;

Replace the above with:

    module MODULE_VAR_EXPORT foo_module;

Note that this will only be activated on Windows, so the module can continue to be used, unchanged, with Unix if needed. Also, if you are familiar with .DEF files, you can export the module record with that method instead.

Now, create a DLL containing your module. You will need to link this against the ApacheCore.lib export library that is created when the ApacheCore.dll shared library is compiled. You may also have to change the compiler settings to ensure that the Apache header files are correctly located.

This should create a DLL version of your module. Now simply place it in the server root, and use the LoadModule directive to load it.

Directives

• LoadFile
• LoadModule

LoadFile

The LoadFile directive links in the named object files or libraries when the server is started; this is used to load additional code which may be required for some module to work. Filename is relative to ServerRoot.

LoadModule

The LoadModule directive links in the object file or library filename and adds the module structure named module to the list of active modules. Module is the name of the external variable of type module in the file. Example:

LoadModule status_module modules/ApacheModuleStatus.dll


Apache HTTP Server Version 1.3