Converts a string to a double-precision floating point value.

#include <stdlib.h>

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

#include <wchar.h>

double wcstod(const wchar_t *nptr, wchar_t **endptr);

Parameters

nptr

String to convert; a sequence of characters that can be interpreted as a numerical value of the specified type.

endptr

End of scan.

Remarks

strtod expects nptr to point to a string with this form:

[whitespace][sign][digits][.digits][{d|D|e|E}[sign]digits]

The first character that does not fit this form stops the scan.

If no conversion can be performed (no valid digits are found or an invalid base is specified), the value of nptr is stored at the location pointed to by endptr.

Return Values

strtod returns the value of the floating-point number, except when the representation would cause an overflow, in which case the function returns +/–HUGE_VAL. The sign of HUGE_VAL matches the sign of the value that cannot be represented. strtod returns 0 if no conversion can be performed or an underflow occurs.

wcstod returns values analogously to strtod. For both functions, errno is set to ERANGE if overflow or underflow occurs.

Generic Text Routines

Requirements