ifx_connect()

(PHP 4, PHP 5 < 5.2.1)

Open Informix server connection

说明

ifx_connect([string $database[,string $userid[,string $password]]]): resource

ifx_connect() establishes a connection to an Informix server.

In case a second call is made to ifx_connect() with the same arguments, no new link will be established, but instead, the link identifier of the already opened link will be returned.

The link to the server will be closed as soon as the execution of the script ends, unless it's closed earlier by explicitly calling ifx_close().

参数

All of the arguments are optional, and if they're missing, defaults are taken from values supplied inphp.ini(ifx.default_host for the host(Informix libraries will useINFORMIXSERVERenvironment value if not defined), ifx.default_user for user, ifx.default_password for the password(none if not defined).

$database: The database name, as a string.
$userid: The username, as a string.
$password: The password, as a string.

返回值

Returns a connection identifier on success, or FALSE on error.

范例

Example #1 Connect to a Informix database

<?php
$conn_id = ifx_connect ("mydb@ol_srv1", "imyself", "mypassword");
?>

参见

ifx_pconnect()Open persistent Informix connection
ifx_close()Close Informix connection

Here's a tip :
When i first installed the informix through the removing the ; at php_ifx.dll and then restarted apache 
then checking the phpinfo(); the connection wasn't established and i had this error that i have to set the INFORMIXSERVER.
Work Frame : Windows XP,Apache 2.2.1 php 5.3 The ODBC was working fine and i could connect to the informix server using the odbc connection
The problem is that the sql engine was on another machine with different platform.
[SOLUTION]
add an environmental variable called INFORMIXSERVER with the value of the server e.g myInformixServer which itself has an ip 192.x.x.x
You can do that on windows by right click on my computer advanced >> environmental variables >> add new System variable >> variable name = INFORMIXSERVER 
variable value = myInformixServer 
it worked like a charm

Problem with INFORMIX-Access with PHP4, WIN NT 4.0?
1. php.ini: extension=php_ifx.dll
2. Path: Informix/BIN
3. httpd.conf: PassEnv INFORMIXSERVER
          PassEnv INFORMIXDIR
4. use the Informix-tool regcopy.exe to copy the registry settings in the system-account.
good luck!