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.
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
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>.
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
The iconv_open() function may fail if:
EMFILE All file descriptors available to the process are currently
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.
The following sections are informative.
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, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/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
IEEE/The Open Group 2013 ICONV_OPEN(3P)