FMOD(3) Library Functions Manual FMOD(3)

fmod, fmodf, fmodl
floating-point remainder functions

#include <math.h>
double
fmod(double x, double y);
float
fmodf(float x, float y);
long double
fmodl(long double x, long double y);

There are three Nm macro lines in the NAME section, each but the last ending in a comma, the comma separated from the name by a blank character.
Do not forget to quote the Fa arguments, or you get commas in the output between the argument types and argument names.
The functions are still simple enough that using the Fn macro would also be acceptable:
#include <math.h> 

double
fmod(double x, double y);
However, for functions taking more than one short argument, using Fo is arguably more readable.
September 27, 2015 bsd.lv