To complement what Jonas said, if there is no room in the currently allocated Free Pascal heap, the system memory manager calls the system specific function SysOSAlloc defined in rtl/unix/sysheap.inc, for unix systems. This in turn calls Fpmmap function which does a syscall syscall_nr_mmap... code is in rtl/linux/ossysc.inc.
None of these two functions are function variables, which would mean that you need to modify the rtl, make SysOSAlloc return nil everytime, alloc enough memory at startup to avoid running out of memory within a run, and recompile it if your memory manager still calls the standard RTL underneath. Of course, if your own memory manager does not call the standard one, you should be safe. Pierre Muller > -----Message d'origine----- > De : fpc-devel-boun...@lists.freepascal.org [mailto:fpc-devel- > boun...@lists.freepascal.org] De la part de Jonas Maebe > Envoyé : Wednesday, January 06, 2010 3:38 PM > À : FPC developers' list > Objet : Re: [fpc-devel] custom ThreadManager and MemoryMutexManager for > hard realtime > > > On 06 Jan 2010, at 15:25, Stefan Kisdaroczi wrote: > > > AFAIK the RTL allocs the heap on app startup, or on thread-creation > > with 2.4.0. > > In my code im using getmem() to alloc mem from the heap, this will > > not generate > > syscalls because the heap is already allocated and the RTL has its > > own MemoryManager. > > This is not entirely correct: while the rtl does pre-allocate some > memory from the system on startup, it can still allocate more later if > necessary, and it can also free memory back to the system. > > > Jonas > _______________________________________________ > fpc-devel maillist - fpc-devel@lists.freepascal.org > http://lists.freepascal.org/mailman/listinfo/fpc-devel _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
