During macro expansion (with arguments), there is one global buffer
(exp_buf) that keeps getting reallocated to fit all the macro's text
that's currently being expanded. The problem with this scheme is that if
a macro with arguments needs to be expanded from the macro text of another
macro with arguments, it may happen that the second expansion forces
the above exp_buf buffer to be reallocated. Which is fine until the
previous macro processing resumes where (struct include_stack_t *)->str
now points to uninitialised memory. Basically, the code that can trigger
such behaviour is as follows:
`define FOO(a) (a+3)
`define BAR(b) (`FOO(b)+2)
`BAR(x)
Ofcourse, you need to get lucky to get the exp_buf to be realloced at the
right point, but it's possible.
I don't see the advantage in keeping all the expanding macro's text
together, so my solution is to simply allocate a new buffer and pass it
as (struct include_stack_t *)->str to the flex parsing function and free
it at the end.
nog