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Flow-IPC 3.0.0
Flow-IPC project: Full implementation reference.
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ipc::shm sub-module providing the SHM-provider family based on the arena-lending paradigm: each process allocates in its own arena(s), lending the resulting objects to other processes, which can read them but not allocate (nor deallocate) in that arena. More...
Namespaces | |
| namespace | detail |
| Segregated private stuff for ipc::shm::arena_lend. | |
| namespace | error |
| Namespace containing the ipc::shm::arena_lend module's (including SHM-jemalloc's) extension of boost.system error conventions, so that that API can return codes/messages from within its own new set of error codes/messages. | |
| namespace | jemalloc |
| ipc::shm sub-module with the SHM-jemalloc SHM-provider. See ipc::shm doc header for introduction. | |
| namespace | stat |
| Stats-related sub-namespace, for ADL segregation and general organization. | |
Classes | |
| class | Borrower_allocator_arena |
When borrowing STL-compliant in-SHM data structures, use this type as the Arena template parameter to shm::stl::Stateless_allocator (or equivalent). More... | |
| struct | Set_logger_tag |
Tag type for the Action_registry that fans out set_logger() calls to all arena-lend singletons. More... | |
| class | Shm_pool_offset_ptr |
Typedefs | |
| template<typename T > | |
| using | Obj_handle = std::shared_ptr< T > |
Determines the shared_ptr variety returned by A::construct() and S::borrow_object() for any arena-lending SHM-provider, where for a given SHM-provider A is the arena type (SHM-jemalloc: jemalloc::Ipc_arena), S is the SHM-session type (SHM-jemalloc: session::shm::arena_lend::jemalloc::Shm_session). More... | |
| using | Shared_name = util::Shared_name |
| Short-hand for util::Shared_name; used in particular for SHM pool names at least. More... | |
| using | owner_id_t = util::process_id_t |
Alias for an identifier of the owner (essentially namespace of collection_id_ts) of shared information. More... | |
| using | collection_id_t = uint32_t |
| Identifier type for a shared memory pool collection. More... | |
| using | Set_logger_registry = flow::util::Action_registry< Set_logger_tag, flow::log::Logger * > |
The Action_registry that fans out set_logger() calls to all SHM-arena-lend singletons. More... | |
Functions | |
| void | set_logger (flow::log::Logger *logger_ptr) |
Convenience function that sets (or clears) the Logger used by all SHM-arena-lend singleton subsystems. More... | |
ipc::shm sub-module providing the SHM-provider family based on the arena-lending paradigm: each process allocates in its own arena(s), lending the resulting objects to other processes, which can read them but not allocate (nor deallocate) in that arena.
As of this writing there is one arena-lending SHM-provider available out-of-the-box, SHM-jemalloc (see sub-namespace arena_lend::jemalloc). The present namespace contains items applicable to any arena-lending provider, with provider-specific items in such sub-namespaces.
On Shm_pool_offset_ptr fwd-declaration, we have a Difference_type = int default. De facto int is the only choice for Difference_type (as this important fancy-pointer type is in-practice used by SHM-jemalloc et al).
It raises some questions: namely: (1) Why is Difference_type configurable at all? (2) Why int specifically? For (1) I (ygoldfel) suspect original author (echan) borrowed this configurability from boost::interprocess::offset_ptr. We do not really need it though. For (2) we are not sure. (It might be something from an older-than-current-min Boost version's – 1.87 as of this writing – bipc::offset_ptr.)
That all may be moot at this point:
Difference_type template-param configurability. There are some rigid constraints, internal to Shm_pool_offset_ptr_data (core of Shm_pool_offset_ptr), on what it can be in practice. Moreover nothing, that we know of, needs this configurability. (offset_ptr has a wider range of use-cases, and no such rigid restrictions, so in its case this configurability makes sense; and/or at least it does not cause questions and worries in the same way.) | using ipc::shm::arena_lend::collection_id_t = typedef uint32_t |
Identifier type for a shared memory pool collection.
collection_id_t into detail/. Definition at line 128 of file arena_lend_fwd.hpp.
| using ipc::shm::arena_lend::Obj_handle = typedef std::shared_ptr<T> |
Determines the shared_ptr variety returned by A::construct() and S::borrow_object() for any arena-lending SHM-provider, where for a given SHM-provider A is the arena type (SHM-jemalloc: jemalloc::Ipc_arena), S is the SHM-session type (SHM-jemalloc: session::shm::arena_lend::jemalloc::Shm_session).
For a given SHM-provider, those 2 APIs are the only sources of first-class a/k/a outer object handles. An outer object is by definition one constructed by an arena A or IPC-transmitted and re-obtained borrower-side via SHM-session S. The a.construct() call involves at least allocating, in SHM, sizeof(T) bytes; further inner allocations are possible if T uses the proper SHM-capable allocator (we recommend stl::Stateless_allocator); for example if T is vector then the vector ctor invocation during a.construct() might perform an inner allocation, as might a subsequent .resize().
| T | Outer object type. |
Definition at line 106 of file arena_lend_fwd.hpp.
| using ipc::shm::arena_lend::owner_id_t = typedef util::process_id_t |
Alias for an identifier of the owner (essentially namespace of collection_id_ts) of shared information.
owner_id_t into detail/. Definition at line 118 of file arena_lend_fwd.hpp.
| using ipc::shm::arena_lend::Set_logger_registry = typedef flow::util::Action_registry<Set_logger_tag, flow::log::Logger*> |
The Action_registry that fans out set_logger() calls to all SHM-arena-lend singletons.
The end user is likely to not need to directly reference this: use arena_lend::set_logger() free function.
Definition at line 135 of file arena_lend_fwd.hpp.
| using ipc::shm::arena_lend::Shared_name = typedef util::Shared_name |
Short-hand for util::Shared_name; used in particular for SHM pool names at least.
Definition at line 109 of file arena_lend_fwd.hpp.
| void ipc::shm::arena_lend::set_logger | ( | flow::log::Logger * | logger_ptr | ) |
Convenience function that sets (or clears) the Logger used by all SHM-arena-lend singleton subsystems.
Typical usage brackets main():
| logger_ptr | Pointer to the Logger to use, or null to disable logging. |
Definition at line 32 of file util.cpp.
Referenced by ipc::session::shm::arena_lend::detail::Borrower_shm_pool_collection_repository< Shm_arena_t >::Borrower_shm_pool_collection_repository(), ipc::shm::arena_lend::jemalloc::Ipc_arena::destroy(), ipc::shm::arena_lend::detail::Thread_lcl_obj_db_admin< Shm_arena_t >::set_logger(), and ipc::shm::arena_lend::detail::Thread_lcl_obj_db_client< Shm_arena_t >::set_logger().
1.9.4