abs(3) Library Functions Manual abs(3)

abs, labs, llabs, imaxabs, uabs, ulabs, ullabs, uimaxabs - compute the absolute value of an integer

Standard C library (libc-lc)

#include <stdlib.h>
int abs(int j);
long labs(long j);
long long llabs(long long j);
unsigned int uabs(int j);
unsigned long ulabs(long j);
unsigned long long ullabs(long long j);
#include <inttypes.h>
intmax_t imaxabs(intmax_t j);
uintmax_t uimaxabs(intmax_t j);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

llabs():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

uabs(), ulabs(), ullabs(), uimaxabs():

    _ISOC2Y_SOURCE

These functions compute the absolute value of the argument j of the appropriate integer type for the function.

Returns the absolute value of the integer argument, of the appropriate integer type for the function.

For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
abs (), labs (), llabs (), imaxabs (), uabs (), ulabs (), ullabs (), uimaxabs () Thread safety MT-Safe

C23, POSIX.1-2024

C89, POSIX.1-1996, SVr4, 4.3BSD.
C89, POSIX.1-2001.
C99, POSIX.1-2001; glibc 2.0.
C99, POSIX.1-2001; glibc 2.1.1.
C2y; glibc 2.42.

For abs(), labs(), llabs(), and imaxabs(), trying to take the absolute value of the most negative integer is not defined.

cabs(3), ceil(3), fabs(3), floor(3), rint(3)

2025-05-06 Linux man-pages 6.14