NAME
strtold() — convert string to long double-precision number
SYNOPSIS
#include <stdlib.h>
long double strtold(const char *str, char **ptr);
DESCRIPTION
strtold()
returns as a long double-precision number
the value represented by the character string pointed to by
str.
The string is scanned up to the first unrecognized character.
strtold()
recognizes an optional string of ``white-space'' characters (as defined by
isspace()
in
ctype(3C)),
then an optional sign,
then a string of digits optionally containing a radix character,
then an optional
e
or
E
followed by an optional sign or space, followed by an integer.
The radix character is determined by the loaded
NLS
environment (see
setlocale(3C)).
If
setlocale()
has not been called successfully, the default
NLS
environment, "C" (see
lang(5)),
is used.
The default environment specifies a period
(.)
as the radix character.
If the value of
ptr
is not
(char **) NULL,
the variable to which it points is set
to point at the character after the last number,
if any, that was recognized.
If no number can be formed,
*ptr
is set to
str,
and zero is returned.
APPLICATION USAGE
strtold()
is thread-safe and async-cancel-safe.
EXTERNAL INFLUENCES
International Code Set Support
Single-byte character code sets are supported.
RETURN VALUE
If the correct value would cause overflow, positive
_LDBL_MAX
or negative
_LDBL_NMAX
is returned (according to the sign of the value), and
errno
is set to
ERANGE.
The
__LDBL_MAX
and
__LDBL_NMAX
macros are provided to assist in checking
the return values against
_LDBL_MAX
and
_LDBL_NMAX.
If the correct value would cause underflow,
_ZERO
is returned and
errno
is set to
ERANGE.
AUTHOR
strtold()
was developed by HP.
