The behaviour of these functions is affected by settings in php.ini.
In order to configure expect extension, there are configuration options in the configuration file php.ini.
Here's a short explanation of the configuration directives.
The timeout period for waiting for the data, when using the expect_expectl() function.
A value of "-1" disables a timeout from occurring.
A value of "0" causes the expect_expectl() function to return immediately.
Whether expect should send any output from the spawned process to stdout. Since interactive programs typically echo their input, this usually suffices to show both sides of the conversation.
Name of the file, where the output from the spawned process will be written. If this file doesn't exist, it will be created.
If this configuration is not empty, the output is written regardless of the value of expect.loguser.
Changes default size (2000 bytes) of the buffer used to match asterisks in patterns.