trunc(3) Library Functions Manual trunc(3)
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 attrib-
utes(7).
┌───────────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├───────────────────────────────────────────┼───────────────┼─────────┤
│ trunc(), truncf(), truncl() │ Thread safety │ MT-Safe │
└───────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
C11, POSIX.1-2008.
HISTORY
glibc 2.1. 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)
Linux man-pages 6.7 2023-10-31 trunc(3)
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