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To: (Jimmey Todd)
Subject: Re: FLEX question regarding istream vs ifstream
In-reply-to: Your message of Mon, 08 Dec 1997 15:54:15 PST.
Date: Mon, 15 Dec 1997 13:21:35 PST
From: Vern Paxson <vern>

>         stdin_handle = YY_CURRENT_BUFFER;
>         ifstream fin( "aFile" );
>         yy_switch_to_buffer( yy_create_buffer( fin, YY_BUF_SIZE ) );
> What I'm wanting to do, is pass the contents of a file thru one set
> of rules and then pass stdin thru another set... It works great if, I
> don't use the C++ classes. But since everything else that I'm doing is
> in C++, I thought I'd be consistent.
> The problem is that 'yy_create_buffer' is expecting an istream* as it's
> first argument (as stated in the man page). However, fin is a ifstream
> object. Any ideas on what I might be doing wrong? Any help would be
> appreciated. Thanks!!

You need to pass &fin, to turn it into an ifstream* instead of an ifstream.
Then its type will be compatible with the expected istream*, because ifstream
is derived from istream.