backslash
int backslash;
backslash = 0;
if (backslash) {
backslash = 0;
backslash++;
case '\n': c = 'n'; goto backslash;
case '\t': c = 't'; goto backslash;
case '\r': c = 'r'; goto backslash;
case '"': c = '"'; goto backslash;
case '\\': c = '\\'; goto backslash;
case CTLESC: c = 'e'; goto backslash;
case CTLVAR: c = 'v'; goto backslash;
case CTLVAR+CTLQUOTE: c = 'V'; goto backslash;
case CTLBACKQ: c = 'q'; goto backslash;
case CTLBACKQ+CTLQUOTE: c = 'Q'; goto backslash;
backslash: putc('\\', tracefile);
char *backslash(char *str);
if (!str || (p = copy = backslash(str)) == NULL)
s->equiv[0] = backslash(s, NULL);
stopval = backslash(s, &octal);
s->lastch = backslash(s, NULL);
s->cnt = backslash(s, NULL);
static int backslash(STR *, int *);
s->lastch = backslash(s, &is_octal);