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From: drears@ardc.arpa (P)
Newsgroups: net.unix-wizards
Subject: 7 option for cc
Message-ID: <1934@brl-smoke.ARPA>
Date: Wed, 19-Mar-86 18:00:55 EST
Article-I.D.: brl-smok.1934
Posted: Wed Mar 19 18:00:55 1986
Date-Received: Sat, 22-Mar-86 05:38:54 EST
Sender: news@brl-smoke.ARPA
Lines: 45


     I work in a 4.2 BSD environment with brl "enhancements".  What this means
is we have access to system V commands and libraries but not to system V
system calls.  On one of the programs I was writing I had the following code:

#include <stdio.h>
.
.
.
.
writeda()
{
	FILE *fopen(), *daction;

	if ((daction = fopen(file,"w"))== NULL){
		fprintf(stderr,"ERROR: Could not create %s\n",file);
		perror("");
	}

	/*  Writes out actual file               */
	fprintf(daction,"                              R & A\n");

.
.
.
	fclose(daction);
}

   I compiled (maked) using the the -O flag (cc -O progname), when I ran the
program that got to the first fprintf statement I got memory fault - core
dump.  After extensive checking of the program for bugs I gave up. I then
ported it over to s System V machine and it worked with no problems.  I then
read the manual page on cc and  read about the -7 option:



     -7      Compile using a 4.2BSD environment (a UNIX System V
             environment is the default.)

AFter recompilng with the -O7 flags I got it to run and have had no problems
since.  The question I have is does the -7 option really do that much? What
does it do?  Could the error be me or the compiler option.  I had never used
-7 before.  I have had no problems with prior programs.

   ..Dennis