trunc(3) — Linux manual page

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)

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Linux man-pages 6.9.1          2024-05-02                       trunc(3)

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

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