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copied!<p>Suppose that <code>root/test</code> contains a file called <code>foo</code>. The call to <code>dent=readdir(dir)</code> sets <code>dent->d_name</code> to <code>"foo"</code>. You already have debugging output that shows this: <code>printf(dent->d_name)</code>¹. Then you try to open <code>foo</code> with <code>fopen</code>, but the file is actually <code>root/test/foo</code>. So this fails every time (unless you happen to also have a file called <code>foo</code> in the current directory).</p> <p>There are two ways to open the right file:</p> <ul> <li><p>Construct the full name of the file by concatenating the argument to <code>opendir</code> with the file name. Something like:</p> <pre><code>/*before */ size_t dir_length = strlen(DIR_PATH); char *filename = malloc(dir_length + NAME_MAX + 2); /*error checking omitted*/ strcpy(filename, DIR_PATH); filename[dir_length] = '/'; filename[dir_length+1] = 0; while ((dent = readdir(dir)) != NULL) { strcpy(filename + dir_length + 1, dent->d_name); /*now call lstat, fopen, etc. on filename*/ </code></pre></li> <li><p>Change into the directory you're listing. For example, change the opendir call to</p> <pre><code>chdir(DIR_PATH); /*error checking omitted*/ dir = opendir("."); </code></pre> <p>You have to remember to save the previous directory with <code>getcwd</code> and <code>chdir</code> back to it afterwards. This method is not recommended in production software because it is possible to have a current directory that you can't <code>chdir</code> back into due to permissions.</p></li> </ul> <p><a href="https://stackoverflow.com/questions/3536781/accessing-directories-in-c/3536853#3536853">slacker has already explained why <code>fopen</code> can't be used to test if a file is a directory.</a></p> <p><sub> ¹ which by the way should be <code>puts(dent->d_name)</code> or even better <code>fputs(dent->d_name, stderr)</code>: your original <code>printf</code> call would break if a file name contains <code>%</code>, which is not a big problem for debugging output but is a bad habit to get into. </sub></p>

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