| sub_of(3) | Library Functions Manual | sub_of(3) |
sub_of - subtract two integers, check for arithmetic overflow
#include <libowfat/rangecheck.h>
int sub_of(dest,a,b);
If calculating a-b is possible without causing undefined behavior or an arithmetic overflow in C, and the result fits into the destination integer type, do dest=a-b and return 0.
Otherwise, return 1.
Note: This is a macro, so dest does not have to be a pointer.
In the multiplication functions, a return value of 1 signals success and 0 failure. In add_of, sub_of and assign it's the other way around.
add_of(3), assign(3), imult16(3), umult16(3), imult32(3), umult32(3), imult64(3), umult64(3)