Error: MakeotfGlyphs(4127) malloc: *** mmap(size=39387136) failed (error code=12)

I was compiling the features when I got this message
after the spinning wheel for 5 minutes.

What does it mean?

Last thing I had added in the code was a liga:
sub @(class) @(20 times a class or so) by 1glyph
8 such long rules

Can you send please me the .glyphs file?

Done; to info …

Can you send it to support@…? Then I can take a look too.

Also thanks for your help.
Much appreciated.

The ligature rule involved too many classes and thus was too complex to be compiled. The resulting subtable exceeded its maximum size allocation.

Just to recap this for a moment:
How many classes is to many?

I have written an other code; and it seems to work on my first tests in multiple programs.
However; I have put this font in FontLab; just for fun; and FontLab can’t export it because of to many possible combinations…

Is there a guideline about how many possible combinations we shouldn’t exceed?

like [class of 26 letters] [class of 26 letters] [class of 26 letters] =17576 possible combinations,…
or one letter may have XX number of listings in the code?

There is no clear answer for this. And I think that the number of glyphs in the class does not matter. Only how many classes.