strtod.3c (2010 09)

s
strtod(3C) strtod(3C)
RETURN VALUE
If the correct value would cause overflow,
strtod() returns +/-HUGE_VAL (equal to +/-
INFINITY), according to the sign of the value, and sets
errno to [ERANGE].
If the correct value would be nonzero but too small in magnitude to represent as a nonzero
double, then
strtod() returns zero and sets errno to [ERANGE]. For Itanium-based system,
strtod() also
sets
errno to [ERANGE] whenever the conversion of its input parameter character string to
double
raises the underflow exception.
When the input parameter character string for
strtod()
, after the optional white space and sign, is
either
INF (case insensitive) or INFINITY (case insensitive)
strtod() will return +/-INFINITY,
according to the sign indicated by the character string.
When the input parameter character string for
strtod()
, after the optional white space and sign, is
NAN (case insensitive),
strtod() will return a quiet NaN.
On Itanium-based systems, these functions round correctly for hexadecimal input strings, and round
correctly for up to 36 significant decimal digits, according to the specification in ISO/IEC C99.
SEE ALSO
ctype(3C), setlocale(3C), scanf(3S), strtol(3C), lang(5), thread_safety(5).
STANDARDS CONFORMANCE
strtod(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, ANSI C
atof(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C
2 Hewlett-Packard Company − 2 − HP-UX 11i Version 3: September 2010