Problem:
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Mono-Threaded COBOL Socket client & server.
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related KB:
Multi-Threaded COBOL socket's server & MonoThreaded COBOL client.
http://supportline.microfocus.com/mf_kb_display.asp?kbnumber=23143
Resolution:
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Mono-Threaded COBOL Socket client & server.
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The program server.cbl is the socket's server ( written in COBOL )
The program client.cbl is the socket's client ( written in COBOL ).
This sample was mainly tested on AIX 5.2.0.0 with Server Express 4.0 SP2 32bits.
To Compile and link the sample
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To compile and link server.cbl & client.cbl, launch cl.sh
cl.sh: cob -xag server.cbl
cob -xag client.cbl
To run the sample
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To run the sample, open 2 UNIX sessions.
Login as root in the first session... this session will launch the socket's server,
the program named server
Login with a 'normal' UserId in the second session... this session will launch the socket's client,
the program named client
socket's server Command Line
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The command-line of the program server is: Usage: server socket-port-number
If, at the prompt,
you type: server or server 0, a socket's port-number of 903 will be used
you type: server 903
the sockets API getservbyname will be used to find the service in etc/services
(The getservbyname subroutine retrieves an entry from the /etc/services file using the
service name as a search key)
!!!! need to add, in etc/services, CobolSocket 903/tcp
you type: server nnn ( nnn not being equal to 0 or 903 )
the sockets API getservbyport will be used to find the service in etc/services
(The getservbyport subroutine retrieves an entry from the /etc/services file using a port
number as a search key)
!!!! need to add, in etc/services, CobolSocket 903/tcp
!!!! The simplest is just to type: server
socket's client Command Line
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The command-line of the program client is: client ServerNameOrAddress port-number
If, at the prompt,
you type: client,
the client program will 'search' the socket's server on the port 903 of the current machine
you type: client aHostName
the client program will 'search' the socket's server on the port 903 of the machine named aHostName
you type: client aHostName 903
sockets API getservbyname will be used to find the service in etc/services
(The getservbyname subroutine retrieves an entry from the /etc/services file using the
service name as a search key)
!!!! need to add, in etc/services, CobolSocket 903/tcp
you type: client aHostName nnn ( nnn not being equal to 0 or 903 )
sockets API getservbyport will be used to find the service in etc/services
(The getservbyport subroutine retrieves an entry from the /etc/services file using a port
number as a search key)
!!!! need to add, in etc/services, CobolSocket 903/tcp
!!!! The simplest is just to type: client
demonstration:
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The base demonstration:
( monothread_V0_socket.tar)
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The Socket's client program sends messages to the Socket's server program which answers to the client
The amended demonstration:
( monothread_V1_socket.tar)
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A 'Message Header' has been included in messages sent on the socket so the socket's client and socket's server can control when it is normal they received this message
This 'Message header' contains
the Server socket's identifier AND the client Socket's identifier AND a message number
Note, if the amended demonstration, constants are defined.
They allow:
to display or not the content of the message header ( display == debug mode )
( constant DebugMode-MsgHeader)
to display or not the content of messages sent and received by the server and client
( constant DispMsgRecvSent )
>>>> Comment or set these constants depending on the need
( 'debug mode' or 'run mode' )
This amended demonstation is just a STEP to the Multi-Threaded COBOL Socket client & server
where this emplementation is used
Addendums:
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The source code contains the URLs leading to descriptions of the sockets APIs.
Another intesreting URL:
http://www.cs.rpi.edu/courses/sysprog/sockets/sock.html
Sockets Tutorial
