nan(), nanf(), nanl()

Return a quiet NaN

Synopsis:

#include <math.h>

double nan( const char *tagp );

float nanf( const char *tagp );

long double nanl( const char *tagp );

libm

Use the -l m option to qcc to link against this library.

The nan(), nanf(), and nanl() functions convert the string pointed to by tagp into a quiet NaN, if available.

Calls to nan() are equivalent to calls to strtod(), as shown below:

This call:	Is equivalent to:
`nan("n-char-sequence")`	`strtod("NAN(n-char-sequence)", (char **) NULL)`
`nan("")`	`strtod("NAN()", (char **) NULL)`
`nan(tagp)`, where `tagp` doesn't point to an n-char sequence or an empty string	`strtod("NAN", (char **) NULL)`

Note: The QNX Neutrino versions of these functions don't interpret n-char sequences, and the results are equivalent to specifying NULL for tagp.

Calls to nanf() and nanl() are equivalent to the corresponding calls to strtof() and strtold().

A quiet NaN, if available, corresponding to the string pointed to by tagp.