Path: utzoo!telly!ddsw1!lll-winken!uunet!tut.cis.ohio-state.edu!DG-RTP.DG.COM!meissner
From: meissner@DG-RTP.DG.COM (Michael Meissner)
Newsgroups: gnu.gcc
Subject: Re: cbreak(?) mode and gcc
Keywords: gcc, less, scrabble, screen mode
Message-ID: <8904281417.AA13699@tiktok.dg.com>
Date: 28 Apr 89 14:17:38 GMT
References: <1776@leah.Albany.Edu>
Sender: daemon@tut.cis.ohio-state.edu
Reply-To: Michael Meissner <meissner@dg-rtp.dg.com>
Distribution: gnu
Organization: Data General (Languages @ Research Triangle Park, NC.)
Lines: 57


In article <1776@leah.Albany.Edu> rds95@leah.Albany.Edu (Robert Seals) writes:
| Hello,
| 
| I've noticed that programs which need to go into cbreak (I think - the
| one that sends chars directly through to the program without a newline
| when entered from a terminal) don't work correctly when compiled with
| gcc 1.34. This would seem to me to be a function of the library routines
| and not the compiler, but both `less' (v97) and `scrabble' (just posted
| to c.s.?) exhibit the same behavior - when compiled with cc, they
| deal with the keyboard as expected, but with gcc, they do nothing til
| return is entered.

This seems to come up every so often.  Usually this comes about
because the include file "/usr/include/sys/ioctl.h" (and others too,
but this is the prime culprit) is not compatible with ANSI.  Since GCC
defaults to the ANSI interpretation, it means that you issue the wrong
ioctl.

In particular, the following macros are the ones with problems (macros
taken from a Sun 3.5 system, since we have one internally):

#define	_IO(x,y)	(IOC_VOID|('x'<<8)|y)
#define	_IOR(x,y,t)	(IOC_OUT|((sizeof(t)&IOCPARM_MASK)<<16)|('x'<<8)|y)
#define	_IORN(x,y,t)	(IOC_OUT|(((t)&IOCPARM_MASK)<<16)|('x'<<8)|y)
#define	_IOW(x,y,t)	(IOC_IN|((sizeof(t)&IOCPARM_MASK)<<16)|('x'<<8)|y)
#define	_IOWN(x,y,t)	(IOC_IN|(((t)&IOCPARM_MASK)<<16)|('x'<<8)|y)
/* this should be _IORW, but stdio got there first */
#define	_IOWR(x,y,t)	(IOC_INOUT|((sizeof(t)&IOCPARM_MASK)<<16)|('x'<<8)|y)
#define	_IOWRN(x,y,t)	(IOC_INOUT|(((t)&IOCPARM_MASK)<<16)|('x'<<8)|y)

/* ... */

#define	TIOCSETC	_IOW(t,17,struct tchars)/* set special characters */
#define	TIOCGETC	_IOR(t,18,struct tchars)/* get special characters */

These macros depend on substituting the argument 'x' into the
character constant, which is what ANSI disallows.  To fix this, you
have a few options:

    1)	Use the -traditional switch, which will tell GCC to do things
	the old fashioned PCC way;

    2)	Use the fixincludes script provided with GCC to repair the
	includes, so they can used with an ANSI compiler.  The
	includes are put into GCC's private directory:

		/usr/local/lib/gcc-include

	which GCC searches before /usr/include.  I have noticed that
	the include files that are fixed don't work with non-ANSI
	compilers or GCC's -traditional switch.
--
Michael Meissner, Data General.
Uucp:		...!mcnc!rti!xyzzy!meissner		If compiles were much
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