Question

I get an error with this istruction:

  dp = opendir ("%APPDATA%/.");

  output: 
  Couldn't open directory: Mo such file or directory.

but I don’t get an erro with this istruction:

dp = opendir ("C:/Users/xrobot/AppData/.");

output:
.
..
Local
LocalLow
Roaming

Why ?

Answer 1

opendir doesn’t expand meta variables like %APPDATA%, the shell does. So such things work from the command line, but not from a program. In your program, you have to use an absolute or relative path.

You can probably obtain the required path with getenv(),

const char *appData = getenv("APPDATA");
if (appData) {
    dp = opendir(appData);
} else {
    /* die or recover */
}