ABS(3) Linux Programmer s Manual ABS(3)
NAME abs, labs, llabs, imaxabs - compute the absolute value of an integer
SYNOPSIS #include <stdlib.h>
int abs(int j); long int labs(long int j); long long int llabs(long long int j);
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
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.
CONFORMING TO SVr4, POSIX.1-2001, 4.3BSD, C99. 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 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 han- dles llabs() and imaxabs() as built-ins.
SEE ALSO cabs(3), ceil(3), fabs(3), floor(3), rint(3)
COLOPHON This page is part of release 3.22 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)