Question

Environment – PHP5.2.17, MySQL5.0.92

I am implementing an error logging framework in my application and I am trying to log errors and warnings to a database.

$db = mysql_connect('host', 'database', 'password');
if (!$db)
{
  log(mysql_error());
}
...continue code

I wanted to test the logging and passed the wrong host to the mysql_connect function. As expected I got the warning on screen

Warning: mysql_connect() [function.mysql-connect]: Unknown MySQL server host 'host' (1) in /path/to/my/php/file.php on line 4

And my log function was called but mysql_error() is null. According to the php manual (http://php.net/manual/en/function.mysql-connect.php), mysql_error() should return the last mysql error. In the manual they even have an example of how to echo the error to the screen using mysql_error().

I tried using mysql_error($db), but it returns an error stating that $db is not defined.

I tried replacing my function with echo mysql_error(); and I doesn’t show anything.

I tried using mysql_errno(); and I get null also.

I know the script is catching the warning because it is outputting it to the screen.

One way to resolve my problem is to store the warning in a variable.

I appreciate any help anyone can provide. Thank you.

UPDATE – 2 SOLUTIONS:

SOLUTION 1: (thank you to Mario for suggesting this in one of his comments to this post)

Use PHP function error_get_last() – reference (http://php.net/manual/en/function.error-get-last.php).

New working code with this solution:

$db = mysql_connect('host', 'database', 'password');
if (!$db)
{
  $error = error_get_last();
  log($error['type'] . ": " . $error['message'] . " in file " . $error['file'] . " on line " . $error['line']);
}
...continue code

SOLUTION 2: (thank you to PauPRO for suggesting this in answer 1 below)

Before using $php_errormsg, we need to set track_errors to 1 in the php.ini file. Just include the following line in your php.ini file

track_errors = 1

Alternatively you can set track_errors to 1 inside the script see below the code with this alternative:

ini_set('track_errors', 1);
$db = mysql_connect('host', 'database', 'password');
if (!$db)
{
  log(mysql_error());
}
...continue code

Both solutions work!!!

Answer 1

Make sure you turn on track_errors before using $php_errormsg:

// Preferably do this in your php.ini file, instead of in code.
ini_set('track_errors', 1); 

$db = mysql_connect('host', 'database', 'password');
if (!$db)
{
    log($php_errormsg);
}