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Unable to open a file with fopen()

Asked 2009-11-17T04:05:27.680
12

I've been trying to open a file and output text, but I keep getting errors. So I thought I would start at the very beginning and just try opening the file. This is my code:

#include <stdio.h>
#include <stdlib.h>
#define CORRECT_PARAMETERS 3

int main(void)
{
    FILE *file;
    file = fopen("TestFile1.txt", "r");
    if (file == NULL) {
        printf("Error");
    }
    fclose(file);
}

When I run the file, "Error" gets printed to the console and that's it. The TestFile1.txt is in the same location as my .exe. How do I fix this?

c file-io fopen stdio
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2 Answers

16

How are you running the file? Is it from the command line or from an IDE? The directory that your executable is in is not necessarily your working directory.

Try using the full path name in the fopen and see if that fixes it. If so, then the problem is as described.

For example:

file = fopen("c:\\MyDirectory\\TestFile1.txt", "r");
file = fopen("/full/path/to/TestFile1.txt", "r");

Or open up a command window and navigate to the directory where your executable is, then run it manually.

As an aside, you can insert a simple (for Windows or Linux/UNIX/BSD/etc respectively):

system ("cd")
system("pwd")

before the fopen to show which directory you're actually in.

answered 2009-11-17T04:08:27.627
2

In addition to the above, you might be interested in displaying your current directory:

int MAX_PATH_LENGTH = 80;
char* path[MAX_PATH_LENGTH];
getcwd(path, MAX_PATH_LENGTH);
printf("Current Directory = %s", path);

This should work without issue on a gcc/glibc platform. (I'm most familiar with that type of platform). There was a question posted here that talked about getcwd & Visual Studio if you're on a Windows type platform.

answered 2009-11-17T04:45:40.070

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