#define _XOPEN_SOURCE
#include <iconv.h>
#include <locale.h>
#include <stdio.h>
#include <wchar.h>

int main(void)
{
    iconv_t ic;
    char jis[3+2] = { 0x1b, 0x24, 0x42 };
    int cu, cl;

    setlocale(LC_CTYPE, "");
    if ((ic = iconv_open("wchar_t", "ISO-2022-JP")) == (iconv_t) -1) {
        perror("iconv_open");
        return 1;
    }
    for (cu = 0x21; cu <= 0x7e; cu++) {
        for (cl = 0x21; cl <= 0x7e; cl++) {
            union {
                int val;
                char buf[sizeof(wchar_t)];
            } wc;
            char *jisp = jis, *wcp = wc.buf;
            size_t il = sizeof(jis), ol = sizeof(wc.buf);
            size_t rv;

            jis[3] = cu;
            jis[4] = cl;
            if ((rv = iconv(ic, &jisp, &il, &wcp, &ol)) == -1) {
                char buf[60];
                sprintf(buf, "iconv(%02x%02x):%d", cu, cl, rv);
                perror(buf);
            } else if (rv > 0) {
                fprintf(stderr, "iconv(%02x%02x): converted in a non-reversible way\n", cu, cl);
            } else {
                int w = wcwidth(wc.val);
                if (w != 2) {
                    printf("width=%d jis=%02x%02x wc=%x\n", w, cu, cl, wc.val);
                }
            }
        }
    }
    iconv_close(ic);
    return 0;
}