TRUNC(3)

NAME
trunc, truncf, truncl - round to integer, toward zero

SYNOPSIS
#include <math.h>

double trunc(double x);
float truncf(float x);
long double truncl(long double x);

Link with -lm.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

trunc(), truncf(), truncl():
    _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
    or cc -std=c99

DESCRIPTION
These functions round x to the nearest integer not larger in absolute value.

RETURN VALUE
These functions return the rounded integer value. If x is integral, infinite, or NaN, x itself is returned.

ERRORS
No errors occur.

VERSIONS
These functions first appeared in glibc in version 2.1.

ATTRIBUTES

  Multithreading (see pthreads(7))
The trunc(), truncf(), and truncl() functions are thread-safe.

CONFORMING TO
C99, POSIX.1-2001.

NOTES
The integral value returned by these functions may be too large to store in an integer type (int, long, etc.). To avoid an overflow, which will produce undefined results, an application should perform a range check on the returned value before assigning it to an integer type.

SEE ALSO
ceil(3), floor(3), lrint(3), nearbyint(3), rint(3), round(3)

COLOPHON
This page is part of release 3.53 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/.