$php_errormsg — The previous error message
$php_errormsg is a variable containing the text of the last error message generated by PHP. This variable will only be available within the scope in which the error occurred, and only if the track_errors configuration option is turned on (it defaults to off).
Note: This variable is only available when track_errors is enabled in php.ini.
If a user defined error handler is set $php_errormsg is only set if the error handler returns FALSE
Example #1 $php_errormsg example
<?php
@strpos();
echo $php_errormsg;
?>
上例的输出类似于：
Wrong parameter count for strpos()