PROLOGThis 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.
NAMEislessequal --- test if x is less than or equal to y
#include <math.h> int islessequal(real-floating x, real-floating y);
DESCRIPTIONThe 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 islessequal(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 VALUEUpon successful completion, the islessequal() macro shall return the value of (x) <= (y). If x or y is NaN, 0 shall be returned.
ERRORSNo errors are defined.
The following sections are informative.
APPLICATION USAGEThe 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 argument shall be an expression of real-floating type.
SEE ALSOisgreater(), isgreaterequal(), isless(), islessgreater(), isunordered() The Base Definitions volume of POSIX.1-2008, <math.h>
COPYRIGHTPortions 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 www.unix.org/online.html .
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