Question

I’m trying the open a relative path in Ubuntu , but after opening the first folder – called 14 – the code fails to open the folder inside – called 15:

int pathsCtr; // number of folders in RelativeArray

char ** RelativeArray; // the folders in the relative path, currently: 

RelativeArray[0] = "14";

RelativeArray[1] = "15";
// some code before 

if (pathsCtr > 0 && flag == TRUE) // then we have a relative path
{
    int j = 0;
    while (j < pathsCtr)  // run until the last path and open every one
    {
        printf("\n%s\n" , RelativeArray[j]);
        dirp = opendir(RelativeArray[j]);  // open all directories until the last one
        if (dirp == NULL)
                return -1;
        j++; // proceed to the next directory
    }

    flag = FALSE; // turn off the flag , we'll never go near this again
}

When j == 0 this line : dirp = opendir(RelativeArray[j]); works and dirp is not NULL.

But when j == 1 that line dirp = opendir(RelativeArray[j]); fails and dirp is NULL .

What am I doing wrong?

EDIT:

Assume that I’m doing malloc for RelativeArray before the above code .

Answer 1

opendir() opens a directory for reading its contents, but it does not change the working directory of the process.

To access a subdirectory, you will have to specify it by its fully path relative to the current working directory (or else its absolute path).

You can probably do this by concatenating your strings with an appropriate separator character.

Since you don’t seem to do anything with the directory stream pointer returned by opendir() other than check that it’s non-null, there’s a good chance this is not the function you want to be using. You may want to look at chdir() instead (man 2 chdir) but do think about any undesired consequences.