create_makefile

Generates the Makefile for your extension, passing along any options and preprocessor constants that you may have generated through other methods.

The target name should correspond the name of the global function name defined within your C extension, minus the Init_. For example, if your C extension is defined as Init_foo, then your target would simply be âfooâ.

If any â/â characters are present in the target name, only the last name is interpreted as the target name, and the rest are considered toplevel directory names, and the generated Makefile will be altered accordingly to follow that directory structure.

For example, if you pass âtest/fooâ as a target name, your extension will be installed under the âtestâ directory. This means that in order to load the file within a Ruby program later, that directory structure will have to be followed, e.g. require 'test/foo'.

The srcprefix should be used when your source files are not in the same directory as your build script. This will not only eliminate the need for you to manually copy the source files into the same directory as your build script, but it also sets the proper target_prefix in the generated Makefile.

Setting the target_prefix will, in turn, install the generated binary in a directory under your RbConfig::CONFIG['sitearchdir'] that mimics your local filesystem when you run make install.

For example, given the following file tree:

ext/
  extconf.rb
  test/
    foo.c

And given the following code:

create_makefile('test/foo', 'test')

That will set the target_prefix in the generated Makefile to âtestâ. That, in turn, will create the following file tree when installed via the make install command:

/path/to/ruby/sitearchdir/test/foo.so

It is recommended that you use this approach to generate your makefiles, instead of copying files around manually, because some third party libraries may depend on the target_prefix being set properly.

The srcprefix argument can be used to override the default source directory, i.e. the current directory. It is included as part of the VPATH and added to the list of INCFLAGS.