boost::corosio::select_context
I/O context using POSIX select() for event multiplexing.
Synopsis
Declared in <boost/corosio/select_context.hpp>
class select_context
: public basic_io_contextDescription
This context provides an execution environment for async operations using the POSIX select() API for I/O event notification. It is available on all POSIX platforms and provides a portable fallback when more efficient platform‐specific APIs (epoll, kqueue) are not available or when explicit portability is desired.
On Linux, both epoll_context and select_context are available, allowing users to choose at runtime:
epoll_context ctx1; // Use epoll (best performance)
select_context ctx2; // Use select (portable, useful for testing)Known Limitations
‐ FD_SETSIZE (~1024) limits maximum concurrent connections ‐ O(n) scanning: rebuilds fd_sets each iteration ‐ Level‐triggered only (no edge‐triggered mode)
Thread Safety
Distinct objects: Safe. Shared objects: Safe, if using a concurrency hint greater than 1.
Example
select_context ctx;
auto ex = ctx.get_executor();
run_async(ex)(my_coroutine());
ctx.run(); // Process all queued workTypes
Name |
Description |
The executor type for this context. |
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Abstract base class for services owned by an execution context. |
Member Functions
Name |
Description |
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Constructors |
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Destructor. |
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Assignment operators |
Return a pointer to the service of type T, or nullptr. |
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Return an executor for this context. |
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Return the memory resource used for coroutine frame allocation. |
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Return true if a service of type T exists. |
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Construct and add a service. |
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Process all ready work items without blocking. |
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Process at most one ready work item without blocking. |
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Restart the context after being stopped. |
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Process all pending work items. |
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Process work items for the specified duration. |
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Process at most one pending work item. |
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Process at most one work item for the specified duration. |
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Process at most one work item until the specified time. |
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Process work items until the specified time. |
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Signal the context to stop processing. |
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Return whether the context has been stopped. |
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Return a reference to the service of type T, creating it if needed. |