man3/mbrlen.3

   1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
   2 .\"
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   8 .\" References consulted:
   9 .\"   GNU glibc-2 source code and manual
  10 .\"   Dinkumware C library reference http://www.dinkumware.com/
  11 .\"   OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html
  12 .\"   ISO/IEC 9899:1999
  13 .\"
  14 .TH MBRLEN 3  1999-07-25 "GNU" "Linux Programmer's Manual"
  15 .SH NAME
  16 mbrlen \- determine number of bytes in next multibyte character
  17 .SH SYNOPSIS
  18 .nf
  19 .B #include <wchar.h>
  20 .sp
  21 .BI "size_t mbrlen(const char *" s ", size_t " n ", mbstate_t *" ps );
  22 .fi
  23 .SH DESCRIPTION
  24 The
  25 .BR mbrlen ()
  26 function inspects at most \fIn\fP bytes of the multibyte
  27 string starting at \fIs\fP and extracts the next complete multibyte character.
  28 It updates the shift state \fI*ps\fP.
  29 If the multibyte character is not the
  30 null wide character, it returns the number of bytes that were consumed from
  31 \fIs\fP.
  32 If the multibyte character is the null wide character, it resets the
  33 shift state \fI*ps\fP to the initial state and returns 0.
  34 .PP
  35 If the \fIn\fP bytes starting at \fIs\fP do not contain a complete multibyte
  36 character,
  37 .BR mbrlen ()
  38 returns \fI(size_t)\ \-2\fP.
  39 This can happen even if
  40 \fIn\fP >= \fIMB_CUR_MAX\fP, if the multibyte string contains redundant shift
  41 sequences.
  42 .PP
  43 If the multibyte string starting at \fIs\fP contains an invalid multibyte
  44 sequence before the next complete character,
  45 .BR mbrlen ()
  46 returns
  47 \fI(size_t)\ \-1\fP and sets \fIerrno\fP to \fBEILSEQ\fP.
  48 In this case,
  49 the effects on \fI*ps\fP are undefined.
  50 .PP
  51 If \fIps\fP is a NULL pointer, a static anonymous state only known to the
  52 .BR mbrlen ()
  53 function is used instead.
  54 .SH RETURN VALUE
  55 The
  56 .BR mbrlen ()
  57 function returns the number of bytes
  58 parsed from the multibyte
  59 sequence starting at \fIs\fP, if a non-null wide character was recognized.
  60 It returns 0, if a null wide character was recognized.
  61 It returns
  62 .I "(size_t)\ \-1"
  63 and sets \fIerrno\fP to \fBEILSEQ\fP, if an invalid multibyte sequence was
  64 encountered.
  65 It returns \fI(size_t)\ \-2\fP if it couldn't parse a complete multibyte
  66 character, meaning that \fIn\fP should be increased.
  67 .SH CONFORMING TO
  68 C99.
  69 .SH NOTES
  70 The behavior of
  71 .BR mbrlen ()
  72 depends on the
  73 .B LC_CTYPE
  74 category of the
  75 current locale.
  76 .SH SEE ALSO
  77 .BR mbrtowc (3)