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():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION

These functions round x to the nearest integer value that is not larger in magnitude than x.

RETURN VALUE

These functions return the rounded integer value, in floating format.
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

For an explanation of the terms used in this section, see attributes(7).
Interface Attribute Value
trunc (), truncf (), truncl () Thread safety MT-Safe

CONFORMING TO

C99, POSIX.1-2001, POSIX.1-2008.

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)

Information

Source
Linux kernel
OS/version
Source updated
September 15, 2017
Page created
February 9, 2018
Page generated
December 2, 2018