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From: news@edvcom.UUCP (News Admin)
Newsgroups: comp.unix.questions
Subject: fopen bug in Interactive ix/386 ?
Keywords: unix,SYSV,ix/386
Message-ID: <314@edvcom.UUCP>
Date: 3 May 89 14:21:06 GMT
Lines: 13


The following pice of code hangs because it tries to fopen() more than
_NFILE files. Insteed of returning a NULL pointer after the 18th call
it returns a 'valid' descriptor and chrashes.
We are using 1.0.6.
Any suggestions, maybe someone at ico.ISC.COM reading this group ?

#include <stdio.h>
#include <fcntl.h>
#include <errno.h>

int a = 1;

int print_iob()
{
        int i, cnt, file;
        
        for (i = 0; i < _NFILE; i++)
        {
                cnt = _iob[ i ]._cnt;
                file = _iob[ i ]._file;
                printf("        FD(%d)   _cnt = %d  _file = %d\n",i,cnt,file);
        }
}

main(argc, argv)
int argc;
char *argv[];
{
        int     fod[ 200 ], i, num_opens;
        FILE    *fd[ 200 ];
        char    *msg;
        
                if (argc == 2)
                        num_opens = atoi(argv[ 1 ]);
                else
                {
                        printf("Specify number of open()'s \n");
                        exit(-1);
                }
                for (i = 0; i < num_opens; i++)
                {
                        fod[ i ] = open("/dev/null",O_WRONLY);
                        printf("errno=%d,variable=%d,FOD(%d)=%d\n",
                                                errno,a,i,fod[ i ]);
                }
                for (i = 0; i < 30; i++)
                {
                        printf("fopen (%d): ",i);
                        fflush(stdout);
                        if (fd[ i ] = fopen("/dev/null","w"))
                        {
                                printf("errno=%d,variable=%d,FD(%d)=%d\n",
                                                errno,a,i,fileno(fd[ i ]));
                                print_iob();
                        }
                        else
                        {
                                printf("fopen(%d) delivered NULL...\n",i);
                                break;
                        }
                }
                getchar();
                exit(0);

}  /* end main() */

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