MBRLEN(3P) POSIX Programmer's Manual MBRLEN(3P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAME
mbrlen -- get number of bytes in a character (restartable)
SYNOPSIS
#include <wchar.h>
size_t mbrlen(const char *restrict s, size_t n,
mbstate_t *restrict ps);
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.1-2008 defers to the ISO C standard.
If s is not a null pointer, mbrlen() shall determine the number of bytes constituting the character pointed to by s. It shall be equiva-
lent to:
mbstate_t internal;
mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);
If ps is a null pointer, the mbrlen() function shall use its own internal mbstate_t object, which is initialized at program start-up to the
initial conversion state. Otherwise, the mbstate_t object pointed to by ps shall be used to completely describe the current conversion
state of the associated character sequence. The implementation shall behave as if no function defined in this volume of POSIX.1-2008 calls
mbrlen().
The behavior of this function is affected by the LC_CTYPE category of the current locale.
The mbrlen() function need not be thread-safe if called with a NULL ps argument.
The mbrlen() function shall not change the setting of errno if successful.
RETURN VALUE
The mbrlen() function shall return the first of the following that applies:
0 If the next n or fewer bytes complete the character that corresponds to the null wide character.
positive If the next n or fewer bytes complete a valid character; the value returned shall be the number of bytes that complete the
character.
(size_t)-2 If the next n bytes contribute to an incomplete but potentially valid character, and all n bytes have been processed. When n
has at least the value of the {MB_CUR_MAX} macro, this case can only occur if s points at a sequence of redundant shift
sequences (for implementations with state-dependent encodings).
(size_t)-1 If an encoding error occurs, in which case the next n or fewer bytes do not contribute to a complete and valid character. In
this case, [EILSEQ] shall be stored in errno and the conversion state is undefined.
ERRORS
The mbrlen() function shall fail if:
EILSEQ An invalid character sequence is detected.
The mbrlen() function may fail if:
EINVAL ps points to an object that contains an invalid conversion state.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
mbsinit(), mbrtowc()
The Base Definitions volume of POSIX.1-2008, <wchar.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan-
dard is the referee document. The original Standard can be obtained online at http://www.unix.org/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/man-pages/reporting_bugs.html .
IEEE
/The Open Group 2013 MBRLEN(3P)