Обсуждение: shared memory allocation - C function
Is it possible to allocate a small chunk of shared memory outside of any pools(i.e. manually alloced & de-alloced) that isvisible to all processes? I would like a small amount to store a mutex and a condition variable that is accessible ina c function from any process. Is there an SPI/API to do this? alan
On Thu, Apr 17, 2014 at 8:04 AM, Alan Nilsson <anilsson@apple.com> wrote:
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Michael
Is it possible to allocate a small chunk of shared memory outside of any pools(i.e. manually alloced & de-alloced) that is visible to all processes? I would like a small amount to store a mutex and a condition variable that is accessible in a c function from any process. Is there an SPI/API to do this?You can allocate a custom amount of shared memory at server initialization using the hook called shmem_startup_hook in ipci.c through a library loaded with shared_preload_libraries. Why not having a look at contrib/pg_stat_statements which is a good example?
Michael
Perfect, thank you.
On Apr 16, 2014, at 9:56 PM, Michael Paquier <michael.paquier@gmail.com> wrote:
On Thu, Apr 17, 2014 at 8:04 AM, Alan Nilsson <anilsson@apple.com> wrote:--Is it possible to allocate a small chunk of shared memory outside of any pools(i.e. manually alloced & de-alloced) that is visible to all processes? I would like a small amount to store a mutex and a condition variable that is accessible in a c function from any process. Is there an SPI/API to do this?You can allocate a custom amount of shared memory at server initialization using the hook called shmem_startup_hook in ipci.c through a library loaded with shared_preload_libraries. Why not having a look at contrib/pg_stat_statements which is a good example?
Michael