TCP/IP API Support › Socket Call Interface for PL/I › Notes

Notes

• Some PL/I compilers limit the length of an external name to 7 characters. Since IDMSOCKI contains 8 characters, this can lead to errors at compile time. These errors can be solved in the following ways:
  • Use the compile option LIMITS(EXTNAME(8)).
  • Use entry point IDMSOCK, which is defined as a synonym to IDMSOCKI.
• If an optional parameter is not to be specified in the parameter list, replace it by an asterisk (*).
• The following pre-defined records are provided during installation to assist in writing socket applications:
  • SOCKET_CALL_INTERFACE—Describes the socket functions, return codes and errno values used to issue all socket requests.
  • SOCKET_MISC_DEFINITIONS—Describes options and flags specific to individual functions.
  • SOCKET_MISC_DEFINITIONS_2—Describes the flags specific to the IOCTL function.
  • SOCKET_SOCKADDR_IN, SOCKET_SOCKADDR_IN6, SOCKET_HOSTENT, SOCKET_SERVENT, SOCKET_TIMEVAL, and SOCKET_ADDRINFO—Describe structures that may be useful for certain socket applications.

  Note: Some of these records contain condition names. To generate the appropriate declare statements, specify the following pre-compiler option:

  EXPAND88=YES
  

• The SOCKET_CALL_INTERFACE record contains fields that can be used for socket call common parameters:
  • function
  • return_code
  • errno
  • reason_code

  Each supported function is represented by a field whose value is the function number. The following example illustrates how to issue a READ socket request using the fields within the SOCKET_CALL_INTERFACE record:

  CALL 'IDMSOCKI' USING (SOCKET_FUNCTION_READ,
                      SOCKET_RETCD,
                      SOCKET_ERRNO,
                      SOCKET_RESNCD,
                      . . .);
  

  Note: The SOCKET_CALL_INT record is identical to the SOCKET_CALL_INTERFACE record except that functions values are defined as condition names instead of fields. Unless storage is critical, the SOCKET_CALL_INTERFACE record should be used.

• The program associated with a server task (a task started by a generic listener) must specify the following:

        PROCEDURE (P1, P2, P3)
          OPTIONS (REENTRANT,FETCHABLE);
  
        DCL (P1,P2,P3)          POINTER;
        DCL SOCKET_PARMS        CHAR(80)          BASED (ADDR(P1));
        DCL SOCKET_DESCRIPTOR   FIXED BINARY(31)  BASED (ADDR(P2));
        DCL SOCKET_RESUME_COUNT FIXED BINARY(31)  BASED (ADDR(P3));