Manpages - abs.3

abs, labs, llabs, imaxabs - compute the absolute value of an integer

  #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

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.

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

POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD. 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. 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.

By default, GCC handles *abs*(), *labs*(), and (since GCC 3.0) *llabs*() and *imaxabs*() as built-in functions.

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

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