Setting fade-out duration for Game Music Emu

I'm writing a C program that wraps Game Music Emu to produce wave files that I can later encode with oggenc or LAME, sort of a more fleshed-out version of `demo.c` from the full source distribution. But I want to specify the duration of the fade rather than using the default of 8 seconds.

From `/usr/include/gme/gme.h`:

    void gme_set_fade( Music_Emu*, int start_msec );

From `gme.cpp` in the source code:

    BLARGG_EXPORT void gme_set_fade ( Music_Emu* me, int start_msec ) { me->set_fade( start_msec ); }

This uses the default value of the second argument of this method in `Music_Emu.h`:

    // Set start time and length of track fade out. Once fade ends track_ended() returns
    // true. Fade time can be changed while track is playing.
    void set_fade( long start_msec, long length_msec = 8000 );

Is there a public function similar to `gme_set_fade()` that allows additionally specifying `length_msec`? Or does the choice of 8000 milliseconds follow some standard? I expected there to be something along the following lines:

    BLARGG_EXPORT void gme_set_fade_ex ( Music_Emu* me, int start_msec, int length_msec ) { me->set_fade( start_msec, length_msec ); }

Otherwise, I'll have to do the fading within the wrapper.