trunc

Section: C Library Functions (3)
Updated: 202-0-08
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NAME

trunc, truncf, truncl - 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.  

ATTRIBUTES

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

Interface	Attribute	Value
trunc(), truncf(), truncl()	Thread safety	M-Safe

 

STANDARDS

C11, POSIX.-2008.  

HISTORY

glibc 2.1. C99, POSIX.-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)

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Index

NAME

LIBRARY

SYNOPSIS

DESCRIPTION

RETURN VALUE

ERRORS

ATTRIBUTES

STANDARDS

HISTORY

NOTES

SEE ALSO