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ICONV(3P)                  POSIX Programmer's Manual                 ICONV(3P)

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
       iconv - codeset conversion function
SYNOPSIS
       #include <iconv.h>
       size_t iconv(iconv_t cd, char **restrict inbuf,
              size_t *restrict inbytesleft, char **restrict outbuf,
              size_t *restrict outbytesleft);

DESCRIPTION
       The iconv() function shall convert the sequence of characters from  one
       codeset,  in  the  array  specified by inbuf, into a sequence of corre-
       sponding characters in another codeset, in the array specified by  out-
       buf.  The  codesets  are  those specified in the iconv_open() call that
       returned the conversion descriptor, cd. The inbuf argument points to  a
       variable  that  points  to  the first character in the input buffer and
       inbytesleft indicates the number of bytes to the end of the  buffer  to
       be  converted.  The outbuf argument points to a variable that points to
       the first available byte in the output buffer  and  outbytesleft  indi-
       cates the number of the available bytes to the end of the buffer.
       For  state-dependent  encodings, the conversion descriptor cd is placed
       into its initial shift state by a  call  for  which  inbuf  is  a  null
       pointer,  or  for which inbuf points to a null pointer. When iconv() is
       called in this way, and if outbuf is not a null pointer or a pointer to
       a  null  pointer,  and outbytesleft points to a positive value, iconv()
       shall place, into the output buffer, the byte sequence  to  change  the
       output  buffer  to its initial shift state. If the output buffer is not
       large enough to hold the entire reset sequence, iconv() shall fail  and
       set errno to [E2BIG].  Subsequent calls with inbuf as other than a null
       pointer or a pointer to a null pointer cause  the  conversion  to  take
       place from the current state of the conversion descriptor.
       If  a  sequence  of  input bytes does not form a valid character in the
       specified codeset, conversion shall stop after  the  previous  success-
       fully  converted character. If the input buffer ends with an incomplete
       character or shift sequence, conversion shall stop after  the  previous
       successfully  converted bytes. If the output buffer is not large enough
       to hold the entire converted input, conversion shall stop just prior to
       the  input  bytes  that  would cause the output buffer to overflow. The
       variable pointed to by inbuf shall be updated to point to the byte fol-
       lowing  the  last  byte  successfully used in the conversion. The value
       pointed to by inbytesleft shall be decremented to reflect the number of
       bytes  still not converted in the input buffer. The variable pointed to
       by outbuf shall be updated to point to the byte following the last byte
       of converted output data. The value pointed to by outbytesleft shall be
       decremented to reflect the number of bytes still available in the  out-
       put  buffer.  For  state-dependent encodings, the conversion descriptor
       shall be updated to reflect the shift state in effect at the end of the
       last successfully converted byte sequence.
       If  iconv()  encounters  a character in the input buffer that is valid,
       but for which an identical character does not exist in the target code-
       set, iconv() shall perform an implementation-defined conversion on this
       character.
RETURN VALUE
       The iconv() function shall update the variables pointed to by the argu-
       ments  to reflect the extent of the conversion and return the number of
       non-identical conversions performed. If the entire string in the  input
       buffer is converted, the value pointed to by inbytesleft shall be 0. If
       the input conversion is stopped due to any conditions mentioned  above,
       the  value  pointed to by inbytesleft shall be non-zero and errno shall
       be set to indicate the condition. If an  error  occurs,  iconv()  shall
       return (size_t)-1 and set errno to indicate the error.
ERRORS
       The iconv() function shall fail if:
       EILSEQ Input  conversion  stopped  due  to  an input byte that does not
              belong to the input codeset.
       E2BIG  Input conversion stopped due to lack of space in the output buf-
              fer.
       EINVAL Input conversion stopped due to an incomplete character or shift
              sequence at the end of the input buffer.

       The iconv() function may fail if:
       EBADF  The cd argument is not a valid open conversion descriptor.

       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       The inbuf argument indirectly points to the memory area which  contains
       the conversion input data. The outbuf argument indirectly points to the
       memory area which is to contain  the  result  of  the  conversion.  The
       objects indirectly pointed to by inbuf and outbuf are not restricted to
       containing data that is directly representable in  the  ISO C  standard
       language  char  data  type. The type of inbuf and outbuf, char **, does
       not imply that the objects pointed to are  interpreted  as  null-termi-
       nated  C strings or arrays of characters.  Any interpretation of a byte
       sequence that represents a character in a given character set  encoding
       scheme  is  done internally within the codeset converters. For example,
       the area pointed to indirectly by inbuf and/or outbuf can  contain  all
       zero octets that are not interpreted as string terminators but as coded
       character data according to the respective codeset encoding scheme. The
       type  of the data ( char, short, long, and so on) read or stored in the
       objects is not specified, but may be inferred for both  the  input  and
       output  data  by  the  converters determined by the fromcode and tocode
       arguments of iconv_open().
       Regardless of the data type inferred by the converter, the size of  the
       remaining  space in both input and output objects (the intbytesleft and
       outbytesleft arguments) is always measured in bytes.
       For implementations that  support  the  conversion  of  state-dependent
       encodings, the conversion descriptor must be able to accurately reflect
       the shift-state in effect at the end of the last successful conversion.
       It  is  not  required that the conversion descriptor itself be updated,
       which would require it to be a pointer type. Thus, implementations  are
       free  to  implement  the  descriptor  as a handle (other than a pointer
       type) by which the conversion information can be accessed and updated.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       iconv_open(),   iconv_close(),   the   Base   Definitions   volume   of
       IEEE Std 1003.1-2001, <iconv.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  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 .

IEEE/The Open Group                  2003                            ICONV(3P)