round(3p) — Linux manual page

ROUND(3P)               POSIX Programmer's Manual               ROUND(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       round, roundf, roundl — round to the nearest integer value in a
       floating-point format

SYNOPSIS         top

       #include <math.h>

       double round(double x);
       float roundf(float x);
       long double roundl(long double x);

DESCRIPTION         top

       The functionality described on this reference page is aligned with
       the ISO C standard. Any conflict between the requirements
       described here and the ISO C standard is unintentional. This
       volume of POSIX.1‐2017 defers to the ISO C standard.

       These functions shall round their argument to the nearest integer
       value in floating-point format, rounding halfway cases away from
       zero, regardless of the current rounding direction.

RETURN VALUE         top

       Upon successful completion, these functions shall return the
       rounded integer value.  The result shall have the same sign as x.

       If x is NaN, a NaN shall be returned.

       If x is ±0 or ±Inf, x shall be returned.

ERRORS         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       The integral value returned by these functions need not be
       expressible as an intmax_t.  The return value should be tested
       before assigning it to an integer type to avoid the undefined
       results of an integer overflow.

       These functions may raise the inexact floating-point exception if
       the result differs in value from the argument.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       feclearexcept(3p), fetestexcept(3p)

       The Base Definitions volume of POSIX.1‐2017, Section 4.20,
       Treatment of Error Conditions for Mathematical Functions,
       math.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group.  In the event of any discrepancy between
       this version and the original IEEE and The Open Group Standard,
       the original IEEE and The Open Group Standard is the referee
       document. The original Standard can be obtained online at
       http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                2017                         ROUND(3P)

Pages that refer to this page: math.h(0p),  rint(3p)

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