Xref: utzoo comp.unix.questions:25175 comp.misc:9991
Path: utzoo!utgpu!watserv1!watmath!att!dptg!lzga!bogatko
From: bogatko@lzga.ATT.COM (George Bogatko)
Newsgroups: comp.unix.questions,comp.misc
Subject: Re: File I/O with lex/yacc
Keywords: lex, yacc, file i/o
Message-ID: <2033@lzga.ATT.COM>
Date: 30 Aug 90 12:22:33 GMT
References: <2320@cirrusl.UUCP> <1990Aug29.122152.1600@virtech.uucp> <1990Aug29.172830.14348@cunixf.cc.columbia.edu>
Organization: AT&T BL Middletown/Lincroft NJ USA
Lines: 25

In article <1990Aug29.172830.14348@cunixf.cc.columbia.edu>, gld@cunixd.cc.columbia.edu (Gary L Dare) writes:
> 
> Is there any way to get around the use of standard input/output in a
> lex file???  The C file generated by lex (from the lexical analyzer

There are two ways.
1.  Use freopen(...stdin) freopen(...stdout).

    freopen("your_in_file", "r", stdin);
    freopen("your_out_file", "w", stderr;

2. use a close/open combination, ala:

	close(0);
	open("your_in_file", ...);
	close(1);
	open("your_out_file", ...);
	blah, blah, blah.

   the second way can be useful if you want to use lex to parse the input from
   a tty line different than your terminal line.

Method 1 is far less messy than method 2.

GB