Date: Thu, 2 May 1996 01:58:26 -0700 (PDT) From: Josh MacDonald <jmacd@deceit.xcf.berkeley.edu> To: freebsd-hackers@freebsd.org Subject: stdio problem Message-ID: <199605020858.BAA05189@deceit.xcf.berkeley.edu>
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In the following code:
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char** argv)
{
if(argc != 2) {
fprintf(stderr, "no\n");
exit(1);
}
close(0);
if(!freopen(argv[1], "r", stdin)) {
perror("freopen");
exit(1);
}
while(fgetc(stdin) != EOF) { }
if(ferror(stdin)) {
perror("stdin");
exit(1);
}
printf("its okay\n");
exit(0);
}
FreeBSD exits "stdin: Bad file descriptor"
Linux, SunOS, ULTRIX, PTX, Solaris, HP-UX, IRIX, etc... all report
"its okay".
I am wondering if either FreeBSD, the rest of the OS's, or no one
is "wrong". The pracical application here is that if you close 0
and then exec GNU diff3 you'll encounter this problem. Is it legal
to close your standard input and then fork/exec other programs?
I was under the impression that is was. Am I defying the laws of
physics if I close(0) and then fork/exec a program expecting to
maybe use its standard input with freopen? I don't think so.
-josh
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