Send an error message somewhere (PHP 3, PHP 4, PHP 5)
bool error_log ( string message [, int message_type [, string destination [, string extra_headers]]] )

Sends an error message to the web server's error log, a TCP port or to a file.



The error message that should be logged.


Says where the error should go. The possible message types are as follows:

表 81. error_log() log types

0 message is sent to PHP's system logger, using the Operating System's system logging mechanism or a file, depending on what the error_log configuration directive is set to. This is the default option.
1 message is sent by email to the address in the destination parameter. This is the only message type where the fourth parameter, extra_headers is used.
2 message is sent through the PHP debugging connection. This option is only available if remote debugging has been enabled. In this case, the destination parameter specifies the host name or IP address and optionally, port number, of the socket receiving the debug information. This option is only available in PHP 3.
3 message is appended to the file destination. A newline is not automatically added to the end of the message string.

The destination. Its meaning depends on the message parameter as described above.


The extra headers. It's used when the message parameter is set to 1. This message type uses the same internal function as mail() does.


如果成功则返回 TRUE,失败则返回 FALSE


例 528. error_log() examples

// Send notification through the server log if we can not
// connect to the database.
if (!Ora_Logon($username, $password)) {
error_log("Oracle database not available!", 0);

// Notify administrator by email if we run out of FOO
if (!($foo = allocate_new_foo())) {
error_log("Big trouble, we're all out of FOOs!", 1,

// other ways of calling error_log():
error_log("You messed up!", 2, "");
error_log("You messed up!", 2, "loghost");
error_log("You messed up!", 3, "/var/tmp/my-errors.log");