NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON
ABS(3) Linux Programmer's Manual ABS(3)
abs, labs, llabs, imaxabs - compute the absolute value of an integer
#include <stdlib.h>
int abs(int j);
long int labs(long int j);
long long int llabs(long long int j);
#include <inttypes.h>
intmax_t imaxabs(intmax_t j);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
llabs(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99
The abs() function computes the absolute value of the integer argument j. The
labs(), llabs() and imaxabs() 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.
SVr4, POSIX.1-2001, 4.3BSD, C99. C89 only includes the abs() and labs()
functions; the functions llabs() and imaxabs() were added in C99.
Trying to take the absolute value of the most negative integer is not defined.
The llabs() function is included in glibc since version 2.0, but is not in
libc5 or libc4. The imaxabs() function is included in glibc since version
2.1.1.
For llabs() to be declared, it may be necessary to define _ISOC99_SOURCE or
_ISOC9X_SOURCE (depending on the version of glibc) before including any
standard headers.
GCC handles abs() and labs() as built-in functions. GCC 3.0 also handles
llabs() and imaxabs() as built-ins.
cabs(3), ceil(3), fabs(3), floor(3), rint(3)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2007-07-26 ABS(3)