var cIdentifierRegexp = regexp.MustCompile("^" + cIdentifierFmt + "$")

// IsCIdentifier tests for a string that conforms the definition of an identifier
// in C. This checks the format, but not the length.
func IsCIdentifier(value string) []string {
	if !cIdentifierRegexp.MatchString(value) {

		"a", "ab", "abc", "a1", "_a", "a_", "a_b", "a_1", "a__1__2__b", "__abc_123",
		"A", "AB", "AbC", "A1", "_A", "A_", "A_B", "A_1", "A__1__2__B", "__123_ABC",
	}
	for _, val := range goodValues {
		if msgs := IsCIdentifier(val); len(msgs) != 0 {
			t.Errorf("expected true for '%s': %v", val, msgs)
		}
	}

	badValues := []string{
		"", "1", "123", "1a",
		"-", "a-", "-a", "1-", "-1", "1_", "1_2",