TRUNC

Section: Linux Programmer's Manual (3)
Updated: 2013-06-21
Index Return to Main Contents
 

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 3.54 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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
VERSIONS
ATTRIBUTES
Multithreading (see pthreads(7))
CONFORMING TO
NOTES
SEE ALSO
COLOPHON

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