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NAME

       iconv - perform character set conversion

SYNOPSIS

       #include <iconv.h>

       size_t iconv(iconv_t cd,
                    char **inbuf, size_t *inbytesleft,
                    char **outbuf, size_t *outbytesleft);

DESCRIPTION

       The argument cd must be a conversion descriptor created using the function iconv_open(3).

       The main case is when inbuf is not NULL and *inbuf is not NULL.  In this case, the iconv()
       function converts the multibyte sequence  starting  at  *inbuf  to  a  multibyte  sequence
       starting  at  *outbuf.   At most *inbytesleft bytes, starting at *inbuf, will be read.  At
       most *outbytesleft bytes, starting at *outbuf, will be written.

       The iconv() function converts one multibyte character at a time, and  for  each  character
       conversion  it  increments  *inbuf  and decrements *inbytesleft by the number of converted
       input bytes, it increments *outbuf and decrements *outbytesleft by the number of converted
       output  bytes,  and  it  updates  the  conversion state contained in cd.  If the character
       encoding of the input is stateful, the iconv() function can also  convert  a  sequence  of
       input  bytes to an update to the conversion state without producing any output bytes; such
       input is called a shift sequence.  The conversion can stop for four reasons:

       1. An invalid multibyte sequence is encountered in the input.  In this case it sets  errno
       to  EILSEQ  and  returns  (size_t) -1.   *inbuf  is  left pointing to the beginning of the
       invalid multibyte sequence.

       2. The input byte sequence has been entirely converted, that  is,  *inbytesleft  has  gone
       down to 0.  In this case iconv() returns the number of nonreversible conversions performed
       during this call.

       3. An incomplete multibyte sequence is encountered  in  the  input,  and  the  input  byte
       sequence  terminates  after  it.   In  this  case  it  sets  errno  to  EINVAL and returns
       (size_t) -1.  *inbuf is left  pointing  to  the  beginning  of  the  incomplete  multibyte
       sequence.

       4.  The  output buffer has no more room for the next converted character.  In this case it
       sets errno to E2BIG and returns (size_t) -1.

       A different case is when inbuf is NULL or *inbuf is NULL,  but  outbuf  is  not  NULL  and
       *outbuf  is  not NULL.  In this case, the iconv() function attempts to set cd's conversion
       state to the initial state and store a corresponding shift sequence at *outbuf.   At  most
       *outbytesleft  bytes,  starting  at *outbuf, will be written.  If the output buffer has no
       more room for this reset sequence,  it  sets  errno  to  E2BIG  and  returns  (size_t) -1.
       Otherwise  it  increments  *outbuf  and  decrements  *outbytesleft  by the number of bytes
       written.

       A third case is when inbuf is NULL or *inbuf is NULL, and outbuf is  NULL  or  *outbuf  is
       NULL.  In this case, the iconv() function sets cd's conversion state to the initial state.

CAVEAT

       The  type  of  inbuf  and  outbuf, char **, does not imply that the objects pointed to are
       interpreted as null-terminated C strings or arrays of characters.  The caller of iconv has
       to  make  sure  that  the  pointers  passed  to  the  function  are suitable for access of
       characters from the appropriate character set.  This includes alignment on platforms  that
       have tight restriction on alignment.

RETURN VALUE

       The  iconv()  function  returns  the number of characters converted in a nonreversible way
       during this call; reversible conversions are not counted.  In case of error, it sets errno
       and returns (size_t) -1.

ERRORS

       The following errors can occur, among others:

       E2BIG  There is not sufficient room at *outbuf.

       EILSEQ An invalid multibyte sequence has been encountered in the input.

       EINVAL An incomplete multibyte sequence has been encountered in the input.

VERSIONS

       This function is available in glibc since version 2.1.

CONFORMING TO

       POSIX.1-2001.

SEE ALSO

       iconv_close(3), iconv_open(3)

COLOPHON

       This  page  is  part of release 3.35 of the Linux man-pages project.  A description of the
       project, and information about reporting bugs, can be found at  http://man7.org/linux/man-
       pages/.