Chapter 18. Distributed Application Processing (DAP)

The subroutines in this section initiate and terminate a distributed application process.

GPEXAP - Execute Application Process

Purpose

Use GPEXAP to execute a Distributed Application Process (DAP) through a connected nucleus on a local or remote node. Depending upon the value of the transfer and/or execute parameter (xferflag), the DAP specified through the name parameter either is executed if the DAP already resides on the node or is transferred to the nucleus's node and then is executed.

If the xferflag parameter is set to 2=TRANSFER_EXECUTE , then the name parameter is interpreted to be the path and filename of the DAP object code on the shell's file system. DAPs transferred to the 6095 nucleus's file system are loaded into memory. DAPs transferred to the RISC System/6000 nucleus's file system are placed in a unique temporary directory and erased when the DAP is terminated. By default this will be the /tmp/.gP/ xxxxx directory where xxxxx is the concatenation of the nucleus identifier and the DAP resource identifier. This will insure that the path to the DAP is unique for all DAPs on a RISC System/6000. In order to provide the user control of the size of the directory that will contain the downloaded DAPs, you may override /tmp/.gP/ with your own path by specifying the DAPPATH default in the External Defaults File (EDF) or by using the -p option of the gPinit command (see The graPHIGS Programming Interface: Technical Reference for information on the gPinit command)

If the xferflag parameter is set to 1=EXECUTE_ONLY , then the name parameter is interpreted to be the path and filename of the DAP object code on the nucleus's file system.

For DAPs targeted for the RISC System/6000, where the xferflag is set to either 1=EXECUTE_ONLY or 2=TRANSFER_EXECUTE , a userid and password on the nucleus's node must be provided for the operation to be performed. The DAPs must be prelinked with any required libraries.

For DAPs targeted for the IBM 6095, the xferflag, userid, and password parameters are ignored and the DAP is transferred and executed in a manner equivalent to the Initiate Application Process (GPINAP) subroutine. The DAPs must be prelinked with any required nonshared libraries. System memory with the specified size is allocated, the specified program module is loaded into the memory and the module is started with the passing of the specified data as its parameter. The program module must reside on a disk that is accessible from the shell as a single file with a format that can be loaded by the control program in the 6090.

As with the GPINAP subroutine, DAPs started with the GPEXAP subroutine can be terminated with the Terminate Application Process (GPTMAP) subroutine.

Parameters

      void main( argc, argv )
         int    argc;
         char * argv[[default]

   arg[o]

   arg[1..n]

   arg[0.. n]

      void main( parmlen, parmptr )
         int    parmlen;
         char * parmptr;