STRTOD(3)                 OpenBSD Programmer's Manual                STRTOD(3)

NAME
     strtod - convert ASCII string to double



SYNOPSIS
     #include <stdlib.h>

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

DESCRIPTION
     The strtod() function converts the initial portion of the string pointed
     to by nptr to double representation.

     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 con-
     sists of an ``E'' or ``e'', followed by an optional plus or minus sign,
     followed by a sequence of digits.

     Leading white-space characters in the string (as defined by the iss-
     pace(3) function) are skipped.

RETURN VALUES
     The strtod() function returns the converted value, if any.

     If endptr is not NULL, a pointer to the character after the last charac-
     ter 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 re-
     turned (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
     atof(3),  atoi(3),  atol(3),  strtol(3),  strtoul(3)

STANDARDS
     The strtod() function conforms to ANSI X3.159-1989 (``ANSI C'').

OpenBSD 2.6                      June 29, 1991                               1