+ if (ch == '\\')
+ {
+ /* Special handling for backslash: a backslash may
+ be the beginning of a formal parameter (of a
+ macro) following another symbol character, with
+ whitespace in between. If that is the case, we
+ output a space before the parameter. Strictly
+ speaking, correct handling depends upon what the
+ macro parameter expands into; if the parameter
+ expands into something which does not start with
+ an operand character, then we don't want to keep
+ the space. We don't have enough information to
+ make the right choice, so here we are making the
+ choice which is more likely to be correct. */
+ if (to + 1 >= toend)
+ {
+ /* If we're near the end of the buffer, save the
+ character for the next time round. Otherwise
+ we'll lose our state. */
+ UNGET (ch);
+ goto tofull;
+ }
+ *to++ = ' ';
+ }
+