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)

                                                                                        sub_of(3)