mirror of https://github.com/mkerrisk/man-pages
95 lines
3.2 KiB
Plaintext
95 lines
3.2 KiB
Plaintext
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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "MBLEN" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" mblen
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.SH NAME
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mblen \- get number of bytes in a character
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.SH SYNOPSIS
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.LP
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\fB#include <stdlib.h>
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.br
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.sp
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int mblen(const char *\fP\fIs\fP\fB, size_t\fP \fIn\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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If \fIs\fP is not a null pointer, \fImblen\fP() shall determine the
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number of bytes constituting the character pointed to by
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\fIs\fP. Except that the shift state of \fImbtowc\fP() is not affected,
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it shall be
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equivalent to:
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.sp
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.RS
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.nf
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\fBmbtowc((wchar_t *)0,\fP \fIs\fP\fB,\fP \fIn\fP\fB);
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\fP
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.fi
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.RE
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.LP
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The implementation shall behave as if no function defined in this
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volume of IEEE\ Std\ 1003.1-2001 calls
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\fImblen\fP().
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.LP
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The behavior of this function is affected by the \fILC_CTYPE\fP category
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of the current locale. For a state-dependent encoding,
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this function shall be placed into its initial state by a call for
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which its character pointer argument, \fIs\fP, is a null
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pointer. Subsequent calls with \fIs\fP as other than a null pointer
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shall cause the internal state of the function to be altered
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as necessary. A call with \fIs\fP as a null pointer shall cause this
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function to return a non-zero value if encodings have state
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dependency, and 0 otherwise. If the implementation employs special
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bytes to change the shift state, these bytes shall not produce
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separate wide-character codes, but shall be grouped with an adjacent
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character. Changing the \fILC_CTYPE\fP category causes the
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shift state of this function to be unspecified.
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.SH RETURN VALUE
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.LP
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If \fIs\fP is a null pointer, \fImblen\fP() shall return a non-zero
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or 0 value, if character encodings, respectively, do or do
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not have state-dependent encodings. If \fIs\fP is not a null pointer,
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\fImblen\fP() shall either return 0 (if \fIs\fP points to
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the null byte), or return the number of bytes that constitute the
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character (if the next \fIn\fP or fewer bytes form a valid
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character), or return -1 (if they do not form a valid character)
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\ and may set \fIerrno\fP to indicate the error. In no case shall
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the value returned be greater than \fIn\fP or the value of
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the {MB_CUR_MAX} macro.
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.SH ERRORS
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.LP
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The \fImblen\fP() function may fail if:
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.TP 7
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.B EILSEQ
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Invalid character sequence is detected.
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.sp
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fImbtowc\fP() , \fImbstowcs\fP() , \fIwctomb\fP() , \fIwcstombs\fP()
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, the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, \fI<stdlib.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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