nan(3) BSD Library Functions Manual nan(3)
NAME
nan -- generate a quiet NaN
SYNOPSIS
#include <math.h> double nan(const char *tagp); long double nanl(const char *tagp); float nanf(const char *tagp);
DESCRIPTION
The nan() functions return a quiet NaN, whose trailing fraction field contains the result of converting tagp to an unsigned integer. If tagp is too large to be contained in the trailing fraction field of the NaN, then the least significant bits of the integer represented by tagp are used.
SPECIAL VALUES
If tagp contains any non-numeric characters, the function returns a NaN whos trailing fraction field is zero. If tagp is empty, the function returns a NaN whos trailing fraction field is zero.
STANDARDS
The nan() functions conform to ISO/IEC 9899:2011. BSD July 01, 2008 BSD
Mac OS X 10.9.1 - Generated Wed Jan 8 20:34:18 CST 2014