redirecting cin

[Phil Edwards]

On Tue, Dec 11, 2001 at 11:11:47AM -0500, Andrew Sutton wrote:
> MyParser parser;
> parser.parser( some_file_stream );

Like Bo says, MyParser::parser should accept an istream argument, not an
ifstream argument.  Then, not only will reading from cin directly "just work"
but it will also open up possibilities for future expansion (e.g., derive
"iTCPIPstream" from istream and parse directly from network streams, etc).


> object. it works (worked) nicely until i upgraded to gcc 3.0.2 and lost the 
> ability to grab the file descriptor from the streambuf. alas... okay enough 

That misfeature is coming back in 3.1, in some form or another.


> the trouble is that it just doesn't work.
[...]
> worked great. now, since i don't get access to the file descriptor, i'm 
> trying to redirect to cin, but like i said: doesn't work so great.

While I'm a big fan of error messages which are more easily readable, I
know for a fact that g++ never prints an error message anywhere close to,
"foo.cc:56: doesn't work so great".

Could you elaborate?


> int MyParser::parse( std::ifstream &file )
> {
> 	std::streambuf *in = std::cin.rdbuf( file.rdbuf() );
> 	yyparse();
> 	std::cin.rdbuf( in );
> }

What does g++ say when handed this code?


Phil

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