strtod - convert ASCII string to double
double strtod(const char *nptr, char **endptr));
The strtod() function converts the initial portion of the
string pointed to by nptr to double representation.
The expected form of the string is optional leading white
space as checked by isspace(3), an optional plus (``+'') or
minus sign (``-'') followed by a sequence of digits option-
ally containing a decimal-point character, optionally fol-
lowed by an exponent. An exponent consists of an ``E'' or
``e'', followed by an optional plus or minus sign, followed
by a non-empty sequence of digits. If the locale is not "C"
or "POSIX", different formats may be used.
The strtod function returns the converted value, if any.
If endptr is not NULL, a pointer to the character after the
last character used in the conversion is stored in the loca-
tion referenced by endptr.
If no conversion is performed, zero is returned and the
value of nptr is stored in the location referenced by
If the correct value would cause overflow, plus or minus
HUGE_VAL is returned (according to the sign of the value),
and ERANGE is stored in errno. If the correct value would
cause underflow, zero is returned and ERANGE is stored in
Overflow or underflow occurred.
atof(3), atoi(3), atol(3), strtol(3), strtoul(3)