ISLESSEQUAL(3P) POSIX Programmer's Manual ISLESSEQUAL(3P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAME
islessequal -- test if x is less than or equal to y
SYNOPSIS
#include <math.h>
int islessequal(real-floating x, real-floating y);
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.1-2008 defers to the ISO C standard.
The islessequal() macro shall determine whether its first argument is less than or equal to its second argument. The value of islesse-
qual(x, y) shall be equal to (x) <= (y); however, unlike (x) <= (y), islessequal(x, y) shall not raise the invalid floating-point exception
when x and y are unordered.
RETURN VALUE
Upon successful completion, the islessequal() macro shall return the value of (x) <= (y).
If x or y is NaN, 0 shall be returned.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
The relational and equality operators support the usual mathematical relationships between numeric values. For any ordered pair of numeric
values, exactly one of the relationships (less, greater, and equal) is true. Relational operators may raise the invalid floating-point
exception when argument values are NaNs. For a NaN and a numeric value, or for two NaNs, just the unordered relationship is true. This
macro is a quiet (non-floating-point exception raising) version of a relational operator. It facilitates writing efficient code that
accounts for NaNs without suffering the invalid floating-point exception. In the SYNOPSIS section, real-floating indicates that the argu-
ment shall be an expression of real-floating type.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
isgreater(), isgreaterequal(), isless(), islessgreater(), isunordered()
The Base Definitions volume of POSIX.1-2008, <math.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
ogy -- 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 Stan-
dard 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 .
IEEE
/The Open Group 2013 ISLESSEQUAL(3P)