'\" t .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) .\" .\" SPDX-License-Identifier: Linux-man-pages-copyleft .\" .\" References consulted: .\" Linux libc source code .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified Mon Mar 29 22:31:13 1993, David Metcalfe .\" Modified Sun Jun 6 23:27:50 1993, David Metcalfe .\" Modified Sat Jul 24 21:45:37 1993, Rik Faith (faith@cs.unc.edu) .\" Modified Sat Dec 16 15:02:59 2000, Joseph S. Myers .\" .TH abs 3 2024-05-02 "Linux man-pages 6.8" .SH NAME abs, labs, llabs, imaxabs \- compute the absolute value of an integer .SH LIBRARY Standard C library .RI ( libc ", " \-lc ) .SH SYNOPSIS .nf .B #include .P .BI "int abs(int " j ); .BI "long labs(long " j ); .BI "long long llabs(long long " j ); .P .B #include .P .BI "intmax_t imaxabs(intmax_t " j ); .fi .P .RS -4 Feature Test Macro Requirements for glibc (see .BR feature_test_macros (7)): .RE .P .BR llabs (): .nf _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L .fi .SH DESCRIPTION The .BR abs () function computes the absolute value of the integer argument \fIj\fP. The .BR labs (), .BR llabs (), and .BR imaxabs () functions compute the absolute value of the argument \fIj\fP of the appropriate integer type for the function. .SH RETURN VALUE Returns the absolute value of the integer argument, of the appropriate integer type for the function. .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .TS allbox; lbx lb lb l l l. Interface Attribute Value T{ .na .nh .BR abs (), .BR labs (), .BR llabs (), .BR imaxabs () T} Thread safety MT-Safe .TE .SH STANDARDS C11, POSIX.1-2008. .SH HISTORY POSIX.1-2001, C99, SVr4, 4.3BSD. .\" POSIX.1 (1996 edition) requires only the .\" .BR abs () .\" function. .P C89 only includes the .BR abs () and .BR labs () functions; the functions .BR llabs () and .BR imaxabs () were added in C99. .SH NOTES Trying to take the absolute value of the most negative integer is not defined. .P The .BR llabs () function is included since glibc 2.0. The .BR imaxabs () function is included since glibc 2.1.1. .P For .BR llabs () to be declared, it may be necessary to define \fB_ISOC99_SOURCE\fP or \fB_ISOC9X_SOURCE\fP (depending on the version of glibc) before including any standard headers. .P By default, GCC handles .BR abs (), .BR labs (), and (since GCC 3.0) .BR llabs () and .BR imaxabs () as built-in functions. .SH SEE ALSO .BR cabs (3), .BR ceil (3), .BR fabs (3), .BR floor (3), .BR rint (3)