abs(3) Library Functions Manual abs(3)
NAME
abs, labs, llabs, imaxabs - compute the absolute value of an integer
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
int abs(int j);
long labs(long j);
long long llabs(long long j);
#include <inttypes.h>
intmax_t imaxabs(intmax_t j);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
llabs():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
DESCRIPTION
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 func-
tion.
RETURN VALUE
Returns the absolute value of the integer argument, of the appropriate
integer type for the function.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│ abs(), labs(), llabs(), imaxabs() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
C11, POSIX.1-2008.
HISTORY
POSIX.1-2001, C99, SVr4, 4.3BSD.
C89 only includes the abs() and labs() functions; the functions llabs()
and imaxabs() were added in C99.
NOTES
Trying to take the absolute value of the most negative integer is not
defined.
The llabs() function is included since glibc 2.0. The imaxabs() func-
tion is included since glibc 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.
By default, GCC handles abs(), labs(), and (since GCC 3.0) llabs() and
imaxabs() as built-in functions.
SEE ALSO
cabs(3), ceil(3), fabs(3), floor(3), rint(3)
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