HP-UX Reference (11i v3 07/02) - 3 Library Functions N-Z (vol 7)

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wcstod(3C) wcstod(3C)
NAME
wcstod(), wcstof(), wcstold() - convert a wide character string to a double-precision number
SYNOPSIS
#include <wchar.h>
double wcstod(const wchar_t *__restrict nptr, wchar_t **__restrict
endptr);
long double wcstold(const wchar_t *__restrict nptr, wchar_t **__restrict
endptr);
Itanium(R)-based Systems Only
float wcstof(const wchar_t *restrict nptr, wchar_t **restrict endptr);
Remarks
These functions are compliant with the UNIX standard Worldwide Portability Interface wide-character for-
matting functions. They parallel the 8-bit character formatting functions defined in strtod(3C), strtold(3C)
and strtof(3C) respectively.
DESCRIPTION
The
wcstod(), wcstof(), and wcstold() functions return the value represented by the wide-
character string pointed to by nptr as a double-precision floating-point number, single-precision floating-
point number, and long double-precision number, respectively. The wide character string is scanned (lead-
ing white-space characters as defined by iswspace() in wctype(3C) are ignored) up to the first unrecog-
nized character. If no conversion can take place, zero is returned.
The wcstod(), wcstof(), and wcstold() functions recognize wide characters in the following
sequence:
1. An optional string of white space wide characters, which are ignored
2. An optional sign followed by one of the following:
• A string of digits optionally containing a radix character, then an optional e or E
fol-
lowed by an optional sign or space, followed by an integer
• A 0x or 0X, then a non-empty sequence of hexadecimal digits optionally containing a
radix character, then an optional binary exponent part
• One of INF or INFINITY, or any other wide string equivalent except for case
• One of NAN or NAN(n-wchar-sequence), or any other wide string ignoring case in the
NAN part, where n-wchar-sequence is:
• digit
• nondigit
• n-wchar-sequence digit
• n-wchar-sequence nondigit
The radix character is determined by the current
NLS environment (see setlocale(3C)). If setlocale()
has not been called successfully, the default
NLS environment, "C", is used (see lang(5)). The default
environment specifies a period (.) as the radix character.
If the value of endptr is not
(wchar_t **)NULL, the variable to which it points is set to point at the
wide character after the last number, if any, that was recognized. If no number can be formed, *endptr is
set to nptr, and zero is returned.
EXTERNAL INFLUENCES
Environment Variables
LC_NUMERIC determines the value of the radix character within the currently loaded NLS environment.
LC_CTYPE determines how wide character codes are interpreted.
International Code Set Support
Single- and multibyte character code sets are supported.
RETURN VALUE
If the correct value would cause overflow, +HUGE_VAL or -HUGE_VAL is returned (according to the sign
of the value), and errno is set to [ERANGE].
If the correct value would cause underflow, zero is returned and errno is set to [ERANGE].
650 Hewlett-Packard Company − 1 − HP-UX 11i Version 3: February 2007