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
       attributes(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)