NAME

SYNOPSIS

double
strtod(const char *nptr, char **endptr);

float
strtof(const char *nptr, char **endptr);

long double
strtold(const char *nptr, char **endptr);

DESCRIPTION

The expected form of the string is an optional plus (‘+’) or minus sign (‘-’) followed by a sequence of digits optionally containing a decimal-point character, optionally followed by an exponent. An exponent consists of an ‘E’ or ‘e’, followed by an optional plus or minus sign, followed by a sequence of digits.

Alternatively, if the portion of the string following the optional plus or minus sign begins with “INF” or “NAN”, ignoring case, it is interpreted as an infinity or a quiet NaN, respectively. The syntax “NAN(s)”, where s is an alphanumeric string, produces the same value as the call nan(“s”); (respectively, nanf(“s”); and nanl(“s”);).

In any of the above cases, leading whitespace characters in the string (as defined by the isspace(3) function) are skipped.

RETURN VALUES

If endptr is not NULL, a pointer to the character after the last character used in the conversion is stored in the location referenced by endptr.

If no conversion is performed, zero is returned and the value of nptr is stored in the location referenced by endptr.

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 errno.

ERRORS

[ERANGE]

Overflow or underflow occurred.

SEE ALSO

STANDARDS

CAVEATS