double
     nan(const char *tagp);

     long double
     nanl(const char *tagp);

     float
     nanf(const char *tagp);

DESCRIPTION

     The nan() functions return a quiet NaN. The character string tagp is con-
     verted to an integer, which is clipped to the range 0 to 255, inclusive.
     This value is used as the NaN code. The NaN code is placed in the 8th
     through 15th most significant bits of the fraction field of the resulting
     NaN.

SPECIAL VALUES

     If tagp is empty, 0 is used for the NaN code.

STANDARDS

     The nan() functions conform to ISO/IEC 9899:1999(E).

BSD                              July 24, 2003                             BSD