isless.3p (3313B)
- '\" et
- .TH ISLESS "3P" 2017 "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
- isless
- \(em test if x is less than y
- .SH SYNOPSIS
- .LP
- .nf
- #include <math.h>
- .P
- int isless(real-floating \fIx\fP, real-floating \fIy\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\(hy2017 defers to the ISO\ C standard.
- .P
- The
- \fIisless\fR()
- macro shall determine whether its first argument is less than its
- second argument. The value of
- .IR isless (\c
- .IR x ,
- .IR y )
- shall be equal to (\fIx\fR)\ <\ (\fIy\fR); however, unlike
- (\fIx\fR)\ <\ (\fIy\fR),
- .IR isless (\c
- .IR x ,
- .IR y )
- shall not raise the invalid floating-point exception when
- .IR x
- and
- .IR y
- are unordered.
- .SH "RETURN VALUE"
- Upon successful completion, the
- \fIisless\fR()
- macro shall return the value of (\fIx\fR)\ <\ (\fIy\fR).
- .P
- If
- .IR x
- or
- .IR y
- is NaN, 0 shall be returned.
- .SH ERRORS
- No errors are defined.
- .LP
- .IR "The following sections are informative."
- .SH EXAMPLES
- None.
- .SH "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,
- .BR real-floating
- indicates that the argument shall be an expression of
- .BR real-floating
- type.
- .SH RATIONALE
- None.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .IR "\fIisgreater\fR\^(\|)",
- .IR "\fIisgreaterequal\fR\^(\|)",
- .IR "\fIislessequal\fR\^(\|)",
- .IR "\fIislessgreater\fR\^(\|)",
- .IR "\fIisunordered\fR\^(\|)"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "\fB<math.h>\fP"
- .\"
- .SH 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 .
- .PP
- 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 .