---
name: "umult64"
section: "3"
platform: "linux"
package: "libowfat-dev"
version: "0.32-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/umult64"
---

# umult64(3)

integer multiplication with overflow checking

## NAME

umult64 - integer multiplication with overflow checking

## SYNTAX

**#include \<libowfat/safemult.h\>**

int **umult64**(uint64 a,uint64 b,uint64\* c);

## DESCRIPTION

umult64 does c=a\*b and returns 1.

In case of an integer overflow, umult64 leaves *c* alone and returns 0.

## SEE ALSO

[imult16(3)](/imult16/3.md), [imult32(3)](/imult32/3.md), [imult64(3)](/imult64/3.md)