NAME¶

sub_of - subtract two integers, check for arithmetic overflow

SYNTAX¶

#include <libowfat/rangecheck.h>

int sub_of(dest,a,b);

DESCRIPTION¶

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.

BUGS¶

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.

SEE ALSO¶

add_of(3), assign(3), imult16(3), umult16(3), imult32(3), umult32(3), imult64(3), umult64(3)