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man:iconv

ICONV(3) Linux Programmer's Manual ICONV(3)

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 iconv() function converts a sequence of characters in one character
     encoding to a sequence of characters  in  another  character  encoding.
     The  cd  argument  is  a conversion descriptor, previously created by a
     call to iconv_open(3); the conversion descriptor defines the  character
     encodings  that iconv() uses for the conversion.  The inbuf argument is
     the address of a variable that points to the  first  character  of  the
     input  sequence;  inbytesleft  indicates  the  number  of bytes in that
     buffer.  The outbuf argument is the address of a variable  that  points
     to  the  first  byte available in the output buffer; outbytesleft indi-
     cates the number of bytes available in the output buffer.
     The main case is when inbuf is not NULL and *inbuf  is  not  NULL.   In
     this  case, the iconv() function converts the multibyte sequence start-
     ing at *inbuf to a multibyte sequence starting  at  *outbuf.   At  most
     *inbytesleft  bytes,  starting  at *inbuf, will be read.  At most *out-
     bytesleft 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  *out-
     bytesleft 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.

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.

ATTRIBUTES

     For   an   explanation   of   the  terms  used  in  this  section,  see
     attributes(7).
     +----------+---------------+-----------------+
     |Interface | Attribute     | Value           |
     +----------+---------------+-----------------+
     |iconv()   | Thread safety | MT-Safe race:cd |
     +----------+---------------+-----------------+
     The iconv() function is MT-Safe, as long as callers arrange for  mutual
     exclusion on the cd argument.

CONFORMING TO

     POSIX.1-2001, POSIX.1-2008.

NOTES

     In  each  series of calls to iconv(), the last should be one with inbuf
     or *inbuf equal to NULL, in order to flush out any partially  converted
     input.
     Although inbuf and outbuf are typed as char **, this does not mean that
     the objects they point can be interpreted as C strings or as arrays  of
     characters:  the  interpretation of character byte sequences is handled
     internally by the conversion functions.  In some encodings, a zero byte
     may be a valid part of a multibyte character.
     The caller of iconv() must ensure that the pointers passed to the func-
     tion are suitable for accessing characters in the appropriate character
     set.   This  includes ensuring correct alignment on platforms that have
     tight restrictions on alignment.

SEE ALSO

     iconv_close(3), iconv_open(3), iconvconfig(8)

COLOPHON

     This page is part of release 4.16 of the Linux  man-pages  project.   A
     description  of  the project, information about reporting bugs, and the
     latest    version    of    this    page,    can     be     found     at
     https://www.kernel.org/doc/man-pages/.

GNU 2017-09-15 ICONV(3)

/data/webs/external/dokuwiki/data/pages/man/iconv.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1

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