[Flex-help] YY_INPUT typing compatibility between 2.5 and 2.6

[Daniel L. <fu...@st...>]

Hi,

I'm trying to help a friend set up autoconf on their project which uses 
flex. I've encountered a kind of a funny situation which is probably 
quite easy to handle, but I don't see the right way to handle it. It has 
to do with his definition of YY_INPUT, which looks like this:

#define YY_INPUT(buf,result,max_size) fussy_inp(buf,&result,max_size)

Later on, he has the function definition:

void fussy_inp(char *buf, int *result, int max_size) { ...

Under flex 2.5, this is the right prototype, but under 2.6 it seems to 
want yy_size_t* instead.

I feel like the right thing to do might be to make it a macro instead of 
a function, but it does some significant computation and has a static 
variable in it, so if I could leave it as a function I'd be happier.

At first I thought I'd use AC_CHECK_TYPE to see if yy_size_t exists but 
I think it does exist in 2.5. My next guess was to try checking the type 
of a struct member, but this is getting to be a hairy amount of code in 
autoconf and I thought I'd check here and see if I'm missing something 
obvious first.

https://stackoverflow.com/questions/52296527/autoconf-check-struct-member-type

Thanks,

-- 
Daniel Lyons