Tribblix: manual page: iconv.3c

ICONV(3C) Standard C Library Functions ICONV(3C)

NAME

iconv - code conversion function

SYNOPSIS

Default

#include <iconv.h>

extern size_t iconv(iconv_t cd, const char **restrict inbuf,
size_t *restrict inbytesleft, char **restrict outbuf,
size_t *restrict outbytesleft);

SUSv3
#include <iconv.h>

size_t iconv(iconv_t cd, char **restrict inbuf,
size_t *restrict inbytesleft, char **restrict outbuf,
size_t *restrict outbytesleft);

DESCRIPTION

The iconv() function converts the sequence of characters from one
code set, in the array specified by inbuf, into a sequence of
corresponding characters in another code set, in the array specified
by outbuf. The code sets are those specified in the iconv_open() call
that returned the conversion descriptor, cd. The inbuf argument
points to a variable that points to the first character in the input
buffer and inbytesleft indicates the number of bytes to the end of
the buffer to be converted. The outbuf argument points to a variable
that points to the first available byte in the output buffer and
outbytesleft indicates the number of the available bytes to the end
of the buffer.

For state-dependent encodings, the conversion descriptor cd is placed
into its initial shift state by a call for which inbuf is a null
pointer, or for which inbuf points to a null pointer. When iconv() is
called in this way, and if outbuf is not a null pointer or a pointer
to a null pointer, and outbytesleft points to a positive value,
iconv() will place, into the output buffer, the byte sequence to
change the output buffer to its initial shift state. If the output
buffer is not large enough to hold the entire reset sequence, iconv()
will fail and set errno to E2BIG. Subsequent calls with inbuf as
other than a null pointer or a pointer to a null pointer cause the
conversion to take place from the current state of the conversion
descriptor.

If a sequence of input bytes does not form a valid character in the
specified code set, conversion stops after the previous successfully
converted character. If the input buffer ends with an incomplete
character or shift sequence, conversion stops after the previous
successfully converted bytes. If the output buffer is not large
enough to hold the entire converted input, conversion stops just
prior to the input bytes that would cause the output buffer to
overflow. The variable pointed to by inbuf is updated to point to the
byte following the last byte successfully used in the conversion.
The value pointed to by inbytesleft is decremented to reflect the
number of bytes still not converted in the input buffer. The variable
pointed to by outbuf is updated to point to the byte following the
last byte of converted output data. The value pointed to by
outbytesleft is decremented to reflect the number of bytes still
available in the output buffer. For state-dependent encodings, the
conversion descriptor is updated to reflect the shift state in effect
at the end of the last successfully converted byte sequence.

If iconv() encounters a character in the input buffer that is legal,
but for which an identical character does not exist in the target
code set, iconv() performs an implementation-defined conversion on
this character.

RETURN VALUES

The iconv() function updates the variables pointed to by the
arguments to reflect the extent of the conversion and returns the
number of non-identical conversions performed. If the entire string
in the input buffer is converted, the value pointed to by inbytesleft
will be 0. If the input conversion is stopped due to any conditions
mentioned above, the value pointed to by inbytesleft will be non-
zero and errno is set to indicate the condition. If an error occurs
iconv() returns (size_t) -1 and sets errno to indicate the error.

ERRORS

The iconv() function will fail if:

EILSEQ
Input conversion stopped due to an input byte that does not
belong to the input code set.

E2BIG
Input conversion stopped due to lack of space in the output
buffer.

EINVAL
Input conversion stopped due to an incomplete character or
shift sequence at the end of the input buffer.

The iconv() function may fail if:

EBADF
The cd argument is not a valid open conversion descriptor.

EXAMPLES

Example 1: Using the iconv() Functions

The following example uses the iconv() functions:

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <iconv.h>
#include <stdlib.h>

/*
* For state-dependent encodings, changes the state of the
* conversion descriptor to initial shift state. Also, outputs
* the byte sequence to change the state to initial state.
* This code is assuming the iconv call for initializing the
* state will not fail due to lack of space in the output buffer.
*/
#define INIT_SHIFT_STATE(cd, fptr, ileft, tptr, oleft) \
{ \
fptr = NULL; \
ileft = 0; \
tptr = to; \
oleft = BUFSIZ; \
(void) iconv(cd, &fptr, &ileft, &tptr, &oleft); \
(void) fwrite(to, 1, BUFSIZ - oleft, stdout); \
}

int
main(int argc, char **argv)
{
iconv_t cd;
char from[BUFSIZ], to[BUFSIZ];
char *from_code, *to_code;
char *tptr;
const char *fptr;
size_t ileft, oleft, num, ret;

if (argc != 3) {
(void) fprintf(stderr,
"Usage: %s from_codeset to_codeset\\n", argv[0]);
return (1);
}

from_code = argv[1];
to_code = argv[2];

cd = iconv_open((const char *)to_code, (const char *)from_code);
if (cd == (iconv_t)-1) {
/*
* iconv_open failed
*/
(void) fprintf(stderr,
"iconv_open(%s, %s) failed\\n", to_code, from_code);
return (1);
}

ileft = 0;
while ((ileft +=
(num = fread(from + ileft, 1, BUFSIZ - ileft, stdin))) > 0) {
if (num == 0) {
/*
* Input buffer still contains incomplete character
* or sequence. However, no more input character.
*/

/*
* Initializes the conversion descriptor and outputs
* the sequence to change the state to initial state.
*/
INIT_SHIFT_STATE(cd, fptr, ileft, tptr, oleft);
(void) iconv_close(cd);

(void) fprintf(stderr, "Conversion error\\n");
return (1);
}

fptr = from;
for (;;) {
tptr = to;
oleft = BUFSIZ;

ret = iconv(cd, &fptr, &ileft, &tptr, &oleft);
if (ret != (size_t)-1) {
/*
* iconv succeeded
*/

/*
* Outputs converted characters
*/
(void) fwrite(to, 1, BUFSIZ - oleft, stdout);
break;
}

/*
* iconv failed
*/
if (errno == EINVAL) {
/*
* Incomplete character or shift sequence
*/

/*
* Outputs converted characters
*/
(void) fwrite(to, 1, BUFSIZ - oleft, stdout);
/*
* Copies remaining characters in input buffer
* to the top of the input buffer.
*/
(void) memmove(from, fptr, ileft);
/*
* Tries to fill input buffer from stdin
*/
break;
} else if (errno == E2BIG) {
/*
* Lack of space in output buffer
*/

/*
* Outputs converted characters
*/
(void) fwrite(to, 1, BUFSIZ - oleft, stdout);
/*
* Tries to convert remaining characters in
* input buffer with emptied output buffer
*/
continue;
} else if (errno == EILSEQ) {
/*
* Illegal character or shift sequence
*/

/*
* Outputs converted characters
*/
(void) fwrite(to, 1, BUFSIZ - oleft, stdout);
/*
* Initializes the conversion descriptor and
* outputs the sequence to change the state to
* initial state.
*/
INIT_SHIFT_STATE(cd, fptr, ileft, tptr, oleft);
(void) iconv_close(cd);

(void) fprintf(stderr,
"Illegal character or sequence\\n");
return (1);
} else if (errno == EBADF) {
/*
* Invalid conversion descriptor.
* Actually, this shouldn't happen here.
*/
(void) fprintf(stderr, "Conversion error\\n");
return (1);
} else {
/*
* This errno is not defined
*/
(void) fprintf(stderr, "iconv error\\n");
return (1);
}
}
}

/*
* Initializes the conversion descriptor and outputs
* the sequence to change the state to initial state.
*/
INIT_SHIFT_STATE(cd, fptr, ileft, tptr, oleft);

(void) iconv_close(cd);
return (0);
}

FILES

/usr/lib/iconv/*.so

conversion modules for 32-bit

/usr/lib/iconv/sparcv9/*.so

conversion modules for 64-bit sparc

/usr/lib/iconv/amd64/*.so

conversion modules for 64-bit amd64

/usr/lib/iconv/geniconvtbl/binarytables/*.bt

conversion binary tables

ATTRIBUTES