trunc - Man Page

round to integer, toward zero

Library

Math library (libm, -lm)

Synopsis

#include <math.h>

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

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 were added in glibc 2.1.

Attributes

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

InterfaceAttributeValue
trunc(), truncf(), truncl()Thread safetyMT-Safe

Standards

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)

Referenced By

ceil(3), floor(3), rint(3), round(3).

The man pages truncf(3) and truncl(3) are aliases of trunc(3).

2022-12-15 Linux man-pages 6.02