trusty (3) nanl.3posix.gz

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NAME
       nan, nanf, nanl - return quiet NaN


SYNOPSIS
       #include <math.h>

       double nan(const char *tagp);
       float nanf(const char *tagp);
       long double nanl(const char *tagp);


DESCRIPTION
       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().


RETURN VALUE
       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.


ERRORS
       No errors are defined.

       The following sections are informative.


EXAMPLES
       None.


APPLICATION USAGE
       None.


RATIONALE
       None.


FUTURE DIRECTIONS
       None.


SEE ALSO
       strtod() , strtold() , the Base Definitions volume of IEEE Std 1003.1-2001, <math.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications Issue 6, Copyright (C) 2001-2003 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 .