C Program To Check File Exists : help!

Hi Experts,
I am trying to figure out if a file exists or not in the current directory.
if it is not present the program should exit.

In shell i used :

Code:

#!/usr/bin/ksh
if [ -f file1 ] ; then printf "ok\n" ; else exit ; fi

What is equivalent in C , please advise,


Like:
#include <stdio.h>
main () {
..
if ..
some logic using fopen("file,r) ... please help.


Thanks,

 

Re: C program to check file condition : help!

Multiple Ways.

Code:

if( access( filename, F_OK ) != -1 ) {
    // filename exists
} else {
    // filename doesn't exist
}

But many other forums also recommend the following solution.

Code:

bool file_exists(const char * filename)
{
    if (FILE * file = fopen(filename, "r")) //Open file for read only
    {
        fclose(file);
        return true;
    }
    return false;
}

Which is not very efficient one.

 

Shabbir,
Thank you , I am getting error while compiling both the program ,
Please advise,

Code:

#include <stdio.h>
main ()
{
if( access( filename, F_OK ) != -1 ) {
    // filename exists
} else {
    // filename doesn't exist
}
}

Code:

ubuntu:# cc filecheck.c -o filecheck
filecheck.c: In function âmainâ:
filecheck.c:4:13: error: âfilenameâ undeclared (first use in this function)
filecheck.c:4:13: note: each undeclared identifier is reported only once for each function it appears in
filecheck.c:4:23: error: âF_OKâ undeclared (first use in this function)
# 

DO I have to declare something, Looks like I am missing something in the c program.
Thanks,

 

Got it .. , Thanks..

Code:

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

main()
{
FILE *fp;

if (( fp = fopen("test1.txt", "r")) == NULL)
{
perror("Can not open FILE!!! ");
return EXIT_FAILURE ;
}
else
{
printf ("File opened for reading: [ OK ].\n");
fclose(fp);

}
return(0);
}