Retrieve an extension identified by a key (string) from a port
#include <wfdqnx/wfdcfg.h>
struct wfdcfg_keyval* wfdcfg_port_get_extension(const struct wfdcfg_port *port, const char *key)
The extension is valid between the time you create and destroy the port.
Pointer to wfdcfg_keyval if the extension was found; NULL if the extension was not found. It's considered acceptable for a port to have no extensions.