trunc(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

TRUNC(3)                Linux Programmer's Manual               TRUNC(3)

NAME         top

       trunc, truncf, truncl - round to integer, toward zero

SYNOPSIS         top

       #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         top

       These functions round x to the nearest integer value that is not
       larger in magnitude than x.

RETURN VALUE         top

       These functions return the rounded integer value, in floating
       format.

       If x is integral, infinite, or NaN, x itself is returned.

ERRORS         top

       No errors occur.

VERSIONS         top

       These functions first appeared in glibc in version 2.1.

ATTRIBUTES         top

       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         top

       C99, POSIX.1-2001, POSIX.1-2008.

NOTES         top

       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         top

       ceil(3), floor(3), lrint(3), nearbyint(3), rint(3), round(3)

COLOPHON         top

       This page is part of release 5.10 of the Linux man-pages project.
       A description of the project, information about reporting bugs,
       and the latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

                               2019-03-06                       TRUNC(3)

Pages that refer to this page: ceil(3)floor(3)rint(3)round(3)