Example 4.7. LC_NUMERIC_DEF

__LC_NUMERIC_DEF(lcnumeric_c, "C",".","","")	
__LC_NUMERIC_DEF(lcnumeric_iso8859_1, "ISO8859-1",	
                ".", ",", "\3")	
__LC_NUMERIC_DEF(lcnumeric_fr, "fr", ",", ".", "\3")	
__LC_INDEX_END(lcnumeric_dummy)	
void const *_get_lc_numeric(void const *null, char const *name) {
    return _findlocale(&lcnumeric_c_index, name);
}
void test_lc_numeric(void) {	
    double pi = 4*atan(1.);	
    char buf[20];	
    /* Test changing decimal point as we shift in and out of French	
     * numeric locale. */	
    EQS(setlocale(LC_NUMERIC, NULL), "C");         /* verify starting point */	
    snprintf(buf, sizeof(buf), "%g", pi); EQS(buf, "3.14159");
    EQI(!setlocale(LC_NUMERIC, "ISO8859-1"), 0);   /* setlocale should work */	
    EQS(setlocale(LC_NUMERIC, NULL), "ISO8859-1");	
    snprintf(buf, sizeof(buf), "%g", pi); EQS(buf, "3.14159");	
    EQI(!setlocale(LC_NUMERIC, "fr"), 0);          /* setlocale should work */	
    EQS(setlocale(LC_NUMERIC, NULL), "fr");	
    snprintf(buf, sizeof(buf), "%g", pi); EQS(buf, "3,14159");	
    EQI(!setlocale(LC_NUMERIC, "C"), 0);           /* setlocale should work */	
    EQS(setlocale(LC_NUMERIC, NULL), "C");	
    snprintf(buf, sizeof(buf), "%g", pi); EQS(buf, "3.14159");	
}