openUTM works on a message-oriented basis and does not start a program unit until a complete message has been received for the program unit. The socket interface is a byte-stream interface.
openUTM therefore requires a communication protocol above and in addition to TCP/IP in order to detect message limits. The UTM socket protocol (USP) provided by openUTM serves this purpose and enables the byte streams received via the socket interface to be converted to messages (see "Structure of the socket protocol header"). TCP/IP is required as the transport protocol.
Sample programs
The socket-client sample programs SOCBSP and USOCV6 and a program unit SOCMIRR for socket partners are supplied with openUTM. SOCMIRR ("socket mirror") returns the received messages to the socket client.
On BS2000 systems, you can find the sources and the object modules for the sample programs in the library SYSLIB.UTM.070.EXAMPLE.
On Unix and Linux systems, SOCBSP (source socbsp.c), USOCV6 (source usocv6.c) and SOCMIRR (source socmirr.c) form part of the sample application. You will find the sources under utmsample/soc-c or utmsample/utm-c (utmsample = directory containing the sample application).
On Windows systems, SOCBSP (source socbsp.c), USOCV6 (source usocv6.c) and SOCMIRR (source socmirr.c) are components of the Quick Start Kit . The sources are located in the directory utmpath\utmsample\soc-c or utmpath\utmsample\utm-c.