topic Re: Program in C in Operating System - HP-UX

Program in C

Henry Chua — Thu, 07 Jul 2005 04:30:36 GMT

Hi Guys,

Is there anyway I can write a program in C to check whether a file exist in a path?
regards
Henry

Re: Program in C

Biswajit Tripathy — Thu, 07 Jul 2005 04:41:15 GMT

# man 2 stat

- Biswajit

Re: Program in C

Amit Agarwal_1 — Thu, 07 Jul 2005 07:12:01 GMT

Yes, as Biswajit said "stat()" is the answer. Here is a small program for the same.
================
#include
#include

int main() {

struct stat bstat;

if (stat("filename", &bstat) < 0) {
fprintf(stderr, "file does not exist\n");
} else {
fprintf(stderr, "file does exist\n");
}
}
===========

-Amit

Re: Program in C

Muthukumar_5 — Thu, 07 Jul 2005 07:26:21 GMT

If you want to check file availablity with c coding then, you can simply use fopen() also as,

#include

main()
{

FILE *fp;
fp=fopen("filename1","r");
if (!fp){
printf ("Filename filename1 is not existing\n");
} else {
printf ("Filename filename1 is existing\n");
}
}

Change filename1 with full path as like "/tmp/test/filenam1" also in fopen().

hth.

Re: Program in C

dirk dierickx — Fri, 08 Jul 2005 01:49:09 GMT

if you want to write this to incorporate it into a script, you should not waste your time doing so. unix has the 'test' command (man test) which has lots of options for checking files.

Re: Program in C

Antoniov. — Sat, 09 Jul 2005 02:05:37 GMT

Hi Henry,
I used same routine of Muthukumar with fopen function. It works with any c and any platform.

Antonio Vigliotti.

Re: Program in C

A. Clay Stephenson — Sat, 09 Jul 2005 17:50:06 GMT

The stat() system call is a much better choice than fopen. First, it's cheaper in terms of system resources but more importantly, fopen() (or open()) could very easily fail even if the file actually exists. How? You specify a mode (e.g. "r") when using fopen(), if the file exists but has only write or execute bits set, your fopen() will fail. Use stat(); if it returns a zero result then the operation was okay; you then use the mode field to determine if the file is a regular file and has the desired permission bits sets. If stat returns a non-zero result then you look at errno and determine why it failed.

Re: Program in C

D Block 2 — Sat, 09 Jul 2005 19:59:20 GMT

I agree w/ Clay.. use the stat(2) system call.. you can also use the fopen(3), if you like.

Re: Program in C

Antoniov. — Sun, 10 Jul 2005 01:27:24 GMT

Clay,
thank you for stat information. I read the help on stat function. I think I'll use that next time.

Antonio Vigliotti

Re: Program in C

Stephen Keane — Tue, 12 Jul 2005 08:18:49 GMT

Don't forget the access(2) system call