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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
NAN(3P) POSIX Programmer's Manual NAN(3P)
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.
nan, nanf, nanl — return quiet NaN
#include <math.h>
double nan(const char *tagp);
float nanf(const char *tagp);
long double nanl(const char *tagp);
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 function call nan("n-char-sequence") shall be equivalent to:
strtod("NAN(n-char-sequence)", (char **) NULL);
The function call nan("") shall be equivalent to:
strtod("NAN()", (char **) NULL)
If tagp does not point to an n-char sequence or an empty string, the
function call shall be equivalent to:
strtod("NAN", (char **) NULL)
Function calls to nanf() and nanl() are equivalent to the
corresponding function calls to strtof() and strtold().
These functions shall return a quiet NaN, if available, with content
indicated through tagp.
If the implementation does not support quiet NaNs, these functions
shall return zero.
No errors are defined.
The following sections are informative.
None.
None.
None.
None.
strtod(3p)
The Base Definitions volume of POSIX.1‐2008, math.h(0p)
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 .
IEEE/The Open Group 2013 NAN(3P)
Pages that refer to this page: math.h(0p)