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STDCKDINT(3) FreeBSD Library Functions Manual STDCKDINT(3) NAME stdckdint - checked integer arithmetic SYNOPSIS #include <stdckdint.h> bool ckd_add(type1 *result, type2 a, type3 b); bool ckd_sub(type1 *result, type2 a, type3 b); bool ckd_mul(type1 *result, type2 a, type3 b); DESCRIPTION The function-like macros ckd_add, ckd_sub, and ckd_mul perform checked integer addition, subtraction, and multiplication, respectively. If the result of adding, subtracting, or multiplying a and b as if their respective types had infinite range fits in type1, it is stored in the location pointed to by result and the macro evaluates to false. Otherwise, the macro evaluates to true and the contents of the location pointed to by result is the result of the operation wrapped to the range of type1. RETURN VALUES The ckd_add, ckd_sub, and ckd_mul macros evaluate to true if the requested operation overflowed the result type and false otherwise. EXAMPLES #include <assert.h> #include <limits.h> #include <stdckdint.h> int main(void) { int result; assert(!ckd_add(&result, INT_MAX, 0)); assert(result == INT_MAX); assert(ckd_add(&result, INT_MAX, 1)); assert(result == INT_MIN); assert(!ckd_sub(&result, INT_MIN, 0)); assert(result == INT_MIN); assert(ckd_sub(&result, INT_MIN, 1)); assert(result == INT_MAX); assert(!ckd_mul(&result, INT_MAX / 2, 2)); assert(result == INT_MAX - 1); assert(ckd_mul(&result, INT_MAX / 2 + 1, 2)); assert(result == INT_MIN); return 0; } HISTORY FreeBSD 14.0-RELEASE-p11 September 5, 2023 FreeBSD 14.0-RELEASE-p11