man3/iconv.3

   1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
   2 .\"
   3 .\" This is free documentation; you can redistribute it and/or
   4 .\" modify it under the terms of the GNU General Public License as
   5 .\" published by the Free Software Foundation; either version 2 of
   6 .\" the License, or (at your option) any later version.
   7 .\"
   8 .\" References consulted:
   9 .\"   GNU glibc-2 source code and manual
  10 .\"   OpenGroup's Single Unix specification
  11 .\"     http://www.UNIX-systems.org/online.html
  12 .\"
  13 .\" 2000-06-30 correction by Yuichi SATO <sato@complex.eng.hokudai.ac.jp>
  14 .\" 2000-11-15 aeb, fixed prototype
  15 .\"
  16 .TH ICONV 3 2001-11-15 "GNU" "Linux Programmer's Manual"
  17 .SH NAME
  18 iconv \- perform character set conversion
  19 .SH SYNOPSIS
  20 .nf
  21 .B #include <iconv.h>
  22 .sp
  23 .BI "size_t iconv(iconv_t " cd ,
  24 .BI "             char **" inbuf ", size_t *" inbytesleft ,
  25 .BI "             char **" outbuf ", size_t *" outbytesleft );
  26 .fi
  27 .SH DESCRIPTION
  28 The argument \fIcd\fP must be a conversion descriptor created using the
  29 function
  30 .BR iconv_open (3).
  31 .PP
  32 The main case is when \fIinbuf\fP is not NULL and \fI*inbuf\fP is not NULL.
  33 In this case, the
  34 .BR iconv ()
  35 function converts the multibyte sequence
  36 starting at \fI*inbuf\fP to a multibyte sequence starting at \fI*outbuf\fP.
  37 At most \fI*inbytesleft\fP bytes, starting at \fI*inbuf\fP, will be read.
  38 At most \fI*outbytesleft\fP bytes, starting at \fI*outbuf\fP, will be written.
  39 .PP
  40 The
  41 .BR iconv ()
  42 function converts one multibyte character at a time, and for
  43 each character conversion it increments \fI*inbuf\fP and decrements
  44 \fI*inbytesleft\fP by the number of converted input bytes, it increments
  45 \fI*outbuf\fP and decrements \fI*outbytesleft\fP by the number of converted
  46 output bytes, and it updates the conversion state contained in \fIcd\fP.
  47 The conversion can stop for four reasons:
  48 .PP
  49 1. An invalid multibyte sequence is encountered in the input.
  50 In this case
  51 it sets \fIerrno\fP to \fBEILSEQ\fP and returns
  52 .IR (size_t)(\-1) .
  53 \fI*inbuf\fP
  54 is left pointing to the beginning of the invalid multibyte sequence.
  55 .PP
  56 2. The input byte sequence has been entirely converted,
  57 that is, \fI*inbytesleft\fP has gone down to 0.
  58 In this case
  59 .BR iconv ()
  60 returns the number of
  61 non-reversible conversions performed during this call.
  62 .PP
  63 3. An incomplete multibyte sequence is encountered in the input, and the
  64 input byte sequence terminates after it.
  65 In this case it sets \fIerrno\fP to
  66 \fBEINVAL\fP and returns
  67 .IR (size_t)(\-1) .
  68 \fI*inbuf\fP is left pointing to the
  69 beginning of the incomplete multibyte sequence.
  70 .PP
  71 4. The output buffer has no more room for the next converted character.
  72 In this case it sets \fIerrno\fP to \fBE2BIG\fP and returns
  73 .IR (size_t)(\-1) .
  74 .PP
  75 A different case is when \fIinbuf\fP is NULL or \fI*inbuf\fP is NULL, but
  76 \fIoutbuf\fP is not NULL and \fI*outbuf\fP is not NULL.
  77 In this case, the
  78 .BR iconv ()
  79 function attempts to set \fIcd\fP's conversion state to the
  80 initial state and store a corresponding shift sequence at \fI*outbuf\fP.
  81 At most \fI*outbytesleft\fP bytes, starting at \fI*outbuf\fP, will be written.
  82 If the output buffer has no more room for this reset sequence, it sets
  83 \fIerrno\fP to \fBE2BIG\fP and returns
  84 .IR (size_t)(\-1) .
  85 Otherwise it increments
  86 \fI*outbuf\fP and decrements \fI*outbytesleft\fP by the number of bytes
  87 written.
  88 .PP
  89 A third case is when \fIinbuf\fP is NULL or \fI*inbuf\fP is NULL, and
  90 \fIoutbuf\fP is NULL or \fI*outbuf\fP is NULL.
  91 In this case, the
  92 .BR iconv ()
  93 function sets \fIcd\fP's conversion state to the initial state.
  94 .SH "RETURN VALUE"
  95 The
  96 .BR iconv ()
  97 function returns the number of characters converted in a
  98 non-reversible way during this call; reversible conversions are not counted.
  99 In case of error, it sets \fIerrno\fP and returns
 100 .IR (size_t)(\-1) .
 101 .SH ERRORS
 102 The following errors can occur, among others:
 103 .TP
 104 .B E2BIG
 105 There is not sufficient room at \fI*outbuf\fP.
 106 .TP
 107 .B EILSEQ
 108 An invalid multibyte sequence has been encountered in the input.
 109 .TP
 110 .B EINVAL
 111 An incomplete multibyte sequence has been encountered in the input.
 112 .SH "CONFORMING TO"
 113 POSIX.1-2001.
 114 .SH "SEE ALSO"
 115 .BR iconv_close (3),
 116 .BR iconv_open (3)