bool login(string userName, string password);
Use this function to log into the SMS gateway. You cannot perform
any actions without logging in, so this will be the first function
you use in your application.
username - The username
specified in the SMS gateway. You can set the username when you
create a standard user.
password - The password
of the user. The password is also set in the SMS gateway during
the creation of the user.
true - if the login is successful.
false - if the username or password is incorrect.
bool loggedin = login("admin","abc123");