Correct argument names of XS preparse()

[ppisar]

preparse C function had prototype:

SV * preparse(SV *dbh, const char *statement, IV ps_return, IV ps_accept, void *foo);

But XS function had a ps_return and ps_accept argument names swapped:

SV *
preparse(dbh, statement, ps_accept, ps_return, foo=Nullch)
SV * dbh

This patch corrects the discrepancy.

[timbunce]

Hello @ppisar.
Won't this potentially break existing code that calls this function?
Wouldn't it be better to change the prototype to match the code?

[pali]

Hi @timbunce! Look at this change properly as it is tricky. It just rename local variables...

Won't this potentially break existing code that calls this function?

... so answer to your question is that it cannot break anything as names of C variables does not matter for C/XS API.

Also if you rename ps_accept variable to whatever it still would work.

Prior this change, generated C code from XS was:

IV ps_accept = (IV)SvIV(ST(2));
IV ps_return = (IV)SvIV(ST(3));
...
RETVAL = preparse(dbh, statement, ps_accept, ps_return, foo);

And after this change it is:

IV ps_return = (IV)SvIV(ST(2));
IV ps_accept = (IV)SvIV(ST(3));
...
RETVAL = preparse(dbh, statement, ps_return, ps_accept, foo);

So ST(2) is still passed as third argument to preparse function and ST(3) as fourth argument, despite what is name of local variable.

[timbunce]

It's easy to see that I've not worked on any XS code for too long. Thanks for the clear explanation @pali!