/*

Apparently, ftell() is affecting the stream position in the wide input case.

The test program below should output

fwrite succeeded
 0: fgetwc returned '1'
    ftell returned 1
 1: fgetwc returned '2'
    ftell returned 2
 2: fgetwc returned '3'
    ftell returned 3
 3: fgetwc returned '4'
    ftell returned 4
 4: fgetwc returned '5'
    ftell returned 5
 5: fgetwc returned '6'
    ftell returned 6
 6: fgetwc returned 'x'
    ftell returned 7
   dump: feof=1  ferror=0  ftell=7

but instead outputs

fwrite succeeded
 0: fgetwc returned '1'
    ftell returned 1
 1: fgetwc returned '2'
    ftell returned 1
 2: fgetwc returned '2'
    ftell returned 1
 3: fgetwc returned '2'
    ftell returned 1
 4: fgetwc returned '2'
    ftell returned 1
 5: fgetwc returned '2'
    ftell returned 1
 6: fgetwc returned '2'
    ftell returned 1
 7: fgetwc returned '2'
    ftell returned 1
 8: fgetwc returned '2'
    ftell returned 1
 9: fgetwc returned '2'
    ftell returned 1

If the line invoking ftell() is disabled, then fgetwc() behaves correctly.

*/

#define _ISOC99_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <wchar.h>
#include <errno.h>

int main(void)
{
	FILE *fp;
	int r, n;

	if (!(fp = fopen("ftell-wideio-bug.test", "w+"))) {
		fprintf(stderr, "fopen failed!\n");
		return EXIT_FAILURE;
	}

	r = fwrite("123456x", 1,  7, fp) -  7;
	fprintf(stderr, "fwrite %s\n", (r < 0) ? "failed" : "succeeded");

	if (!(fp = freopen("ftell-wideio-bug.test", "r", fp))) {
		fprintf(stderr, "freopen failed!\n");
		return EXIT_FAILURE;
	}

	if (!setlocale(LC_ALL,"en_US.UTF-8")) {
		fprintf(stderr, "setlocale failed!\n");
		return EXIT_FAILURE;
	}

	n = 0;
	do {
		wint_t w = fgetwc(fp);

		if (w == WEOF) {
			fprintf(stderr, "   dump: feof=%d  ferror=%d  ftell=%ld\n",
					feof(fp) != 0, ferror(fp) != 0, (long) ftell(fp));
			break;
		}

		fprintf(stderr, "%2d: fgetwc returned '%lc'\n", n, w);
#if 0
		ftell(fp);
#elif 1
		fprintf(stderr, "    ftell returned %ld\n", (long) ftell(fp));
#endif
	} while (++n < 10);

	return 0;
}