NAME
nan,
nanf,
nanl —
return quiet NaN
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <math.h>
double
nan(
const char
*tagp);
float
nanf(
const char
*tagp);
long double
nanl(
const char
*tagp);
DESCRIPTION
The call
nan(
"n-char-sequence") is
equivalent to the call
strtod(
"NAN(n-char-sequence)",
NULL). The call
nan(
"") is equivalent to the
call
strtod(
"NAN()",
NULL).
The
nanf() and
nanl() functions are
equivalent to
nan() but substituting
strtof() and
strtold(), respectively.
RETURN VALUES
IEEE 754
The
nan(),
nanf(), and
nanl() functions return a quiet NaN as specified by
tagp.
VAX
The
nan(),
nanf(), and
nanl() functions return zero.
SEE ALSO
math(3),
strtod(3)
STANDARDS
The
nan(),
nanf(), and
nanl() functions conform to
ISO/IEC
9899:1999 (“ISO C99”).