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HP OpenVMS Systemsask the wizard |
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The Question is: Hi Wizard, I am new to open vms, and I am now involved in migrating applications from vax/vms to open vms on alpha 7.1. I have all the source code and I have been successfull in recomiling and linking all the applications which r written in fortran, pascal and c. These applications uses the same addresses (i.e the start address and the end address) in the inadr arguments of the $crmpsc and the SEC$M_EXPREG is not set. while running the application gives a runtime error invalid arguments. after setting the sec$M_EXPREG flag the error goes off , but mapping is not taking place. the other process is not able to fetch the record placed by this process in the global section. The manual says the end address of the inadr argument should be 1 less than the end os the cpu specific page boundary.this application is written in pascal. I am not able to figure out or understand how to set the inadr[0] aligned on a cpu specific page boundary and the inadr[1] with the end of the cpu-specific page.the $getsyi for my system returned 8192. I seem to be badly struct with this and I would apprecite a lot if this can be illustrated with a pascal example. Thank u HN Prasanna The Answer is : The OpenVMS Wizard would first recommend reviewing for the errors discussed in topic (1661), and -- if this is memory shared among multiple processes -- topic (2681). The easiest approach is to use position independence and particularly the SEC$M_EXPREG/SEC$V_EXPREG option setting, and entirely avoid specifying the range of virtual memory to map the section into. A C example of shared memory is available at the main page of the Ask The Wizard area. Also please see existing discussions of $crmpsc including topics (4487), (4051), (3791), (3635), (3365), (2486), (2637), (2181), (860), and others. Also seriously consider using RMS and global buffers, as this can resolve a variety of synchronization problems, and can also operate (correctly) across nodes operating in an OpenVMS Cluster configuration. Also please review the application migration documentation materials in (the archived section of) the OpenVMS documentation website, as that documentation also covers correctly handling the differences in the memory page sizes.
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