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TRUNC(3) Linux Programmer's Manual 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 unde‐
fined 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)
2021-03-22 TRUNC(3)