lipkis (02/05/83)
Those who wish to do real-time programming may like to know that we have successfully run Eunice programs (written entirely in Eunice C) that share memory using VAX/VMS global sections. These shared sections are created and accessed using the SYS$CRMPSC and SYS$MGBLSC system services available as functions in the standard C library. This fact, together with the ability to do the VMS delay and timer services, may make Eunice a reasonable alternative for real-time pro- gramming. We tested the shared-memory processes two ways: In one case we had two separate programs that were invoked in parallel, while in the other we had one program that created the global section, mapped to it and then forked a child (an unlikely mixture of Unix and VMS system calls). We discovered that the child process did not inherit the mapping to the shared section, but it could successfully map to it using SYS$MGBLSC. If you would like to see the code that does this or want more information send mail (do not use reply) to: ...!cmcl2!acf2!condict Michael N. Condict Courant Institute, N.Y.U. 251 Mercer St. New York, New York (212) 460-7239