FLOOR(3)                   POSIX Programmer's Manual                  FLOOR(3)



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

NAME
       floor, floorf, floorl -- floor function

SYNOPSIS
       #include <math.h>

       double floor(double _x);
       float floorf(float _x);
       long double floorl(long double _x);

DESCRIPTION
       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 compute the largest integral value not greater
       than _x.

RETURN VALUE
       The result shall have the same sign as _x.

       Upon successful completion, these functions shall return the largest
       integral value not greater than _x, expressed as a double, float, or
       long double, as appropriate for the return type of the function.

       If _x is NaN, a NaN shall be returned.

       If _x is +-0 or +-Inf, _x shall be returned.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       The integral value returned by these functions might 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
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       ceil(), feclearexcept(), fetestexcept(), isnan()

       Section 4.20, Treatment of Error Conditions for Mathematical Functions,
       <math.h>

COPYRIGHT
       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                             FLOOR(3)
