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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 optional leading white space as
checked by isspace(3), 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 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 char‐
acter 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.
ANSI C
atof(3), atoi(3), atol(3), strtol(3), strtoul(3)