This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       Some  implementations  of  iconv_open()  use  malloc()  to  allocate space for internal buffer areas. The
       iconv_open() function may fail if there is insufficient storage space to accommodate these buffers.

       Conforming applications must assume that conversion descriptors are not valid after a call to one of  the
       exec functions.

       Application  developers  should  consult the system documentation to determine the supported codesets and
       their naming schemes.

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 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 .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                    ICONV_OPEN(3POSIX)

       The  iconv_open()  function  shall  return  a  conversion descriptor that describes a conversion from the
       codeset specified by the string pointed to by the fromcode argument  to  the  codeset  specified  by  the
       string  pointed to by the tocode argument. For state-dependent encodings, the conversion descriptor shall
       be in a codeset-dependent initial shift state, ready for immediate use with iconv().

       Settings of fromcode and tocode and their permitted combinations are implementation-defined.

       A conversion descriptor shall remain valid until it is closed by iconv_close() or an implicit close.

       If a file descriptor is used to implement conversion descriptors, the FD_CLOEXEC flag shall be  set;  see
       <fcntl.h>.

       The iconv_open() function may fail if:

       EMFILE All file descriptors available to the process are currently open.

       ENFILE Too many files are currently open in the system.

       ENOMEM Insufficient storage space is available.

       EINVAL The conversion specified by fromcode and tocode is not supported by the implementation.

       Thefollowingsectionsareinformative.

       None.

       None.

       iconv_open — codeset conversion allocation function

       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.

       None.

       Upon successful completion, iconv_open() shall return a conversion descriptor for use on subsequent calls
       to iconv().  Otherwise, iconv_open() shall return (iconv_t)-1 and set errno to indicate the error.

iconv(), iconv_close()

       The Base Definitions volume of POSIX.1‐2017, <fcntl.h>, <iconv.h>

       #include <iconv.h>

       iconv_t iconv_open(const char *tocode, const char *fromcode);