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.TH FLOOR "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"

.SH PROLOG

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.

.SH NAME

floor,

floorf,

floorl

\(em floor function

.SH SYNOPSIS

.LP

.nf

#include <math.h>

.P

double floor(double \fIx\fP);

float floorf(float \fIx\fP);

long double floorl(long double \fIx\fP);

.fi

.SH 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\(hy2008 defers to the ISO\ C standard.

.P

These functions shall compute the largest integral value not greater

than

.IR x .

.SH "RETURN VALUE"

The result shall have the same sign as

.IR x .

.P

Upon successful completion, these functions shall return the largest

integral value not greater than

.IR x ,

expressed as a

.BR double ,

.BR float ,

or

.BR "long double" ,

as appropriate for the return type of the function.

.P

If

.IR x

is NaN, a NaN shall be returned.

.P

If

.IR x

is \(+-0 or \(+-Inf,

.IR x

shall be returned.

.SH ERRORS

No errors are defined.

.LP

.IR "The following sections are informative."

.SH EXAMPLES

None.

.SH "APPLICATION USAGE"

The integral value returned by these functions might not be expressible

as an

.BR intmax_t .

The return value should be tested before assigning it to an integer

type to avoid the undefined results of an integer overflow.

.P

These functions may raise the inexact floating-point exception if the

result differs in value from the argument.

.SH RATIONALE

None.

.SH "FUTURE DIRECTIONS"

None.

.SH "SEE ALSO"

.IR "\fIceil\fR\^(\|)",

.IR "\fIfeclearexcept\fR\^(\|)",

.IR "\fIfetestexcept\fR\^(\|)",

.IR "\fIisnan\fR\^(\|)"

.P

.IR "Section 4.19" ", " "Treatment of Error Conditions for Mathematical Functions",

.IR "\fB<math.h>\fP"

.SH COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form

from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology

-- Portable Operating System Interface (POSIX), The Open Group Base

Specifications Issue 7, Copyright (C) 2013 by the Institute of

Electrical and Electronics Engineers, Inc and The Open Group.

(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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 .