Type: integer
Default: 0 (0ms)
Min: 0 (0ms)
Max: 2147483647 (2147483647ms)
Unit: milliseconds (ms)
Context: user
Restart: false
Since: 12

Specifies the amount of time that transmitted data may remain unacknowledged before the TCP connection is forcibly closed. If this value is specified without units, it is taken as milliseconds. A value of 0 (the default) selects the operating system's default. This parameter is supported only on systems that support TCP_USER_TIMEOUT (which does not include Windows); on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero.