iconv_open man page


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.

iconv_open — codeset conversion allocation function


#include <iconv.h>

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


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>.

Return Value

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.


The iconv_open() function may fail if:

All file descriptors available to the process are currently open.
Too many files are currently open in the system.
Insufficient storage space is available.
The conversion specified by fromcode and tocode is not supported by the implementation.

The following sections are informative.

Application Usage

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.

See Also

iconv(), iconv_close()

The Base Definitions volume of POSIX.1‐2008, <fcntl.h>, <iconv.h>