WCSTOUL
Section: POSIX Programmer's Manual (3P)
Updated: 2017
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PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
wcstoul,
wcstoull
- convert a wid-character string to an unsigned long
SYNOPSIS
#include <wchar.h>
unsigned long wcstoul(const wchar_t *restrict nptr,
wchar_t **restrict endptr, int base);
unsigned long long wcstoull(const wchar_t *restrict nptr,
wchar_t **restrict endptr, int base);
DESCRIPTION
The functionality described on this reference page is aligned with the
ISO C standard. Any conflict between the requirements described here and the
ISO C standard is unintentional. This volume of POSIX.1-2017 defers to the ISO C standard.
The
wcstoul()
and
wcstoull()
functions shall convert the initial portion of the wid-character
string pointed to by
nptr
to
unsigned long
and
unsigned long long
representation, respectively. First, they shall decompose the input
wid-character string into three parts:
- 1.
-
An initial, possibly empty, sequence of whit-space wid-character
codes (as specified by
iswspace())
- 2.
-
A subject sequence interpreted as an integer represented in some radix
determined by the value of
base
- 3.
-
A final wid-character string of one or more unrecognized
wid-character codes, including the terminating null wid-character
code of the input wid-character string
Then they shall attempt to convert the subject sequence to an
unsigned integer, and return the result.
If
base
is 0, the expected form of the subject sequence is that of a decimal
constant, octal constant, or hexadecimal constant, any of which may be
preceded by a
'+'
or
'-'
sign. A decimal constant begins with a no-zero digit, and consists of
a sequence of decimal digits. An octal constant consists of the prefix
'0'
optionally followed by a sequence of the digits
'0'
to
'7'
only. A hexadecimal constant consists of the prefix 0x or 0X followed
by a sequence of the decimal digits and letters
'a'
(or
'A')
to
'f'
(or
'F')
with values 10 to 15 respectively.
If the value of
base
is between 2 and 36, the expected form of the subject sequence is a
sequence of letters and digits representing an integer with the radix
specified by
base,
optionally preceded by a
'+'
or
'-'
sign, but not including an integer suffix. The letters from
'a'
(or
'A')
to
'z'
(or
'Z')
inclusive are ascribed the values 10 to 35; only letters whose ascribed
values are less than that of
base
shall be permitted. If the value of
base
is 16, the wid-character codes 0x or 0X may optionally precede the
sequence of letters and digits, following the sign if present.
The subject sequence is defined as the longest initial subsequence of
the input wid-character string, starting with the first wid-character
code that is not white space and is of the expected form. The subject
sequence contains no wid-character codes if the input wid-character
string is empty or consists entirely of whit-space wid-character
codes, or if the first wid-character code that is not white space is
other than a sign or a permissible letter or digit.
If the subject sequence has the expected form and
base
is 0, the sequence of wid-character codes starting with the first
digit shall be interpreted as an integer constant. If the subject
sequence has the expected form and the value of
base
is between 2 and 36, it shall be used as the base for conversion,
ascribing to each letter its value as given above. If the subject
sequence begins with a
<hyphe-minus>,
the value resulting from the
conversion shall be negated. A pointer to the final wid-character
string shall be stored in the object pointed to by
endptr,
provided that
endptr
is not a null pointer.
In other than the C
or POSIX
locale, additional local-specific subject sequence forms may be
accepted.
If the subject sequence is empty or does not have the expected form, no
conversion shall be performed; the value of
nptr
shall be stored in the object pointed to by
endptr,
provided that
endptr
is not a null pointer.
These functions shall not change the setting of
errno
if successful.
Since 0,
{ULONG_MAX},
and
{ULLONG_MAX}
are returned on error and 0 is also a valid return on success, an
application wishing to check for error situations should set
errno
to 0, then call
wcstoul()
or
wcstoull(),
then check
errno.
RETURN VALUE
Upon successful completion, the
wcstoul()
and
wcstoull()
functions shall return the converted value, if any. If no conversion
could be performed, 0 shall be returned
and
errno
may be set to indicate the error.
If the correct value is outside the range of representable values,
{ULONG_MAX}
or
{ULLONG_MAX}
respectively shall be returned and
errno
set to
[ERANGE].
ERRORS
These functions shall fail if:
- EINVAL
-
The value of
base
is not supported.
- ERANGE
-
The value to be returned is not representable.
These functions may fail if:
- EINVAL
-
No conversion could be performed.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
fscanf(),
iswalpha(),
wcstod(),
wcstol()
The Base Definitions volume of POSIX.1-2017,
<wchar.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.-2017, Standard for Information Technology- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/ma-pages/reporting_bugs.html .
Index
- PROLOG
-
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- EXAMPLES
-
- APPLICATION USAGE
-
- RATIONALE
-
- FUTURE DIRECTIONS
-
- SEE ALSO
-
- COPYRIGHT
-
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