// vim:ft=doxygen
/**
\ingroup pbdrv
\ingroup pbdrv-mod
\defgroup pb_ext Extensions
\brief Platform-specific \ref pbdrv implementations

Extensions provide platform-specific implementations for various functions used
in \ref pbdrv, and allows \ref pbdrv to remain completely portable. Extensions
are used in both \ref pbdrv and \ref pbdrv-mod.

In order to use an extension, include the appropriate CMake lists file for your
target platform after the \ref pbdrv include:

```cmake
# include pbdrv
add_subdirectory(lib/pbdrv)

# use stdlib extension (for use with C standard library)
include(lib/pbdrv/ext/stdlib/include.cmake)

```

*/