[RESOLVED] Returning a value from a function...

[chris_zeman]

I'm calling a function that connects to my MySQL server and should return a value telling my script whether or not it was able to connect. It doesn't seem to be working, however. The only thing that it displays is

Connected to DB Server: 

😕 Everything looks OK to me, but then again I'm no expert. 😃

Thank you,
Chris

Function:

	function connect_to_db_server()
  	{
  		global $db_host, $db_user, $db_pass;

	$db_server_connected = @mysql_connect($db_host, $db_user, $db_pass);

	return $db_server_connected;
}

Excerpt from script:

			case "upload":
				if ($_FILES["file"]["error"] > 0)
				{
					echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
				}
				else
				{
					echo "Upload: " . $_FILES["file"]["name"] . "<br />";
					echo "Type: " . $_FILES["file"]["type"] . "<br />";
					echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
					echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";

				if (file_exists("media/" . $_FILES["file"]["name"]))
				{
					echo $_FILES["file"]["name"] . " already exists. ";
				}
				else
				{
					move_uploaded_file($_FILES["file"]["tmp_name"], "media/" . $_FILES["file"]["name"]);
					echo "Stored in: " . "media/" . $_FILES["file"]["name"] . "<br />";
				}
			}

			connect_to_db_server();
			echo "Connected to DB Server: " . $db_server_connected;
		break;

[rsmith]

Well you don't assign any real value to be outputted by $db_server_connected whether it connects or doesn't connect. I'm not very good with functions but wouldn't you need to put something like:

return $db_server_connected = "True";

That way the screen would say "Connected to DB Server: True" if it was able to connect.

[laserlight]

Actually, I think the implementation of connect_to_db_server() is okay (though I am uneasy about the use of global variables). Rather:

connect_to_db_server();
echo "Connected to DB Server: " . $db_server_connected;

should be something like:

$db_server_connected = connect_to_db_server() ? 'connected' : 'not connected';
echo "Connected to DB Server: " . $db_server_connected;

The reason you get a blank is that $db_server_connected is undefined. To help you detect and debug such mistakes, keep error_reporting at E_ALL in php.ini

[chris_zeman]

Thank you very much, rsmith!!! You say you're not good, but you're better than me! 🙂

I had to do exactly as you said, but I also needed to make my $db_server_connected a global variable.

Here is my code for anybody else who may run into the same trouble.

function connect_to_db_server()
{
	global $db_host, $db_user, $db_pass, $db_server_connected;

$db_server_connected = @mysql_connect($db_host, $db_user, $db_pass);

if ($db_server_connected == 0)
{
	return $db_server_connected = "False";
}
else
{
	return $db_server_connected = "True";
}
}

Thank you,
Chris

[chris_zeman]

Thank you, laserlight!!! You're code works great for me as well!!! Is one way better than the other for any reason, or does it not make a difference?

Thank you,
Chris

[laserlight]

Is one way better than the other for any reason, or does it not make a difference?

rsmith's solution is incorrect as it will return the string "True" even if a connection could not be made.

[chris_zeman]

Yeah, I noticed that. I understood what he was saying, though, and wrote an 'if' statement to generate the correct condition. I was in the process of that when you posted your original reply, so then I put your code in my program. It remains in my program and is working great for me.

Thanks again!
Chris

[laserlight]

I understood what he was saying, though, and wrote an 'if' statement to generate the correct condition. I was in the process of that when you posted your original reply, so then I put your code in my program. It remains in my program and is working great for me.

That's good. The bad part about returning a string is that it is rather statically a string. If you want it to say "connected" instead of "True", you have to do a little more work. In your original code connect_to_db_server() actually returns what mysql_connect() returns, which is a result resource or false if the connection failed. This can be more flexible, but it is just a matter of design, not correctness.