Documentation :: get API of libraries

[Jonas Melian]

where can i get documentation about the API of the libraries?

ar t /usr/lib/modules/libddc.a

xf86DDC.o
edid.o
interpret_edid.o
print_edid.o
interpret_vdif.o
print_vdif.o
ddcProperty.o

I want know the API of those libs.

thanks in advance