NAME

iconv_open — codeset conversion allocation function

SYNOPSIS

#include <iconv.h>

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


DESCRIPTION

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().

The codeset names that can be specified in fromcode and tocode and their permitted combinations are implementation-defined. Any one of the following indicator suffixes can be appended to the codeset name in tocode:

//IGNORE

Discard input bytes that do not form a valid character or shift sequence, and discard input characters for which an identical character does not exist in the output codeset.

//NON_IDENTICAL_DISCARD

Discard input characters for which an identical character does not exist in the output codeset.

//TRANSLIT

Transliterate input characters for which an identical character does not exist in the output codeset into one or more characters of the output codeset that best resemble the input character.

See the description of iconv() for details of how these indicator suffixes alter the conversion performed by iconv(). Additional implementation-defined indicator suffixes may be supported.

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.

ERRORS

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]

Conversion from the codeset specified in fromcode to the codeset specified in tocode is not supported by the implementation, or the codeset name in tocode is followed by an indicator suffix that is unrecognized or not supported.

EXAMPLES

None.

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.

Some implementations of iconv_open() allow appending multiple indicator suffixes to the codeset name in tocode, and some allow appending an indicator suffix (or suffixes) in both fromcode and tocode. Portable applications should append at most one indicator suffix, and append it only in tocode.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

iconv, iconv_close

XBD <fcntl.h>, <iconv.h>

CHANGE HISTORY

First released in Issue 4. Derived from the HP-UX Manual.

Issue 7

SD5-XBD-ERN-4 is applied, changing the definition of the [EMFILE] error.

The iconv_open() function is moved from the XSI option to the Base.

Issue 8

Austin Group Defect 1007 is applied, adding support for indicator suffixes in the tocode argument to iconv_open().