How to find file path in exe

I am creating dynamic config file through exe.My application was connecting to database every thing working fine.But i need to check the config file is exists or not. I need to develop some logic depends on that config file i need to check every time while exe is starting.
How can i find the config file is exists,How to find the config path in exe.?

Something like this

$exe_file = exo_getglobalvariable("HEPublicationFile", "0");

$config_path_parts = explode("\\",$exe_file);

$config_file_last = count($config_paht_parts)-1;

$config_path_parts[$config_file_last] = "config.ini";

$config_file = implode("\\",$config_path_parts);

or if you know exe file name

$config_file = str_replace("\\my_app.exe","\\config.ini");

Is it not easier if you do it like this:

$myPath     = exo_getglobalvariable('HEPubStorageLocation', '');
$configPath = '/CONFIG/config.ini') // CONFIG is a Subfolder
$configFile = $myPath.$configPath;
/*
 e.g.:
yourexe.exe
|- CONFIG DIR
|-- config.ini
*/

if(file_exists($configFile) {
    echo "CONFIG IS HERE!";
} else {
    echo "NO CONFIG FILE FOUND!";
}

?

HEPubStorageLocation is not equal to where is exe file.