22 lines
1.4 KiB
Markdown
22 lines
1.4 KiB
Markdown
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boost.context
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=============
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boost.context is a foundational library that provides a sort of cooperative multitasking on a single thread.
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By providing an abstraction of the current execution state in the current thread, including the stack (with
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local variables) and stack pointer, all registers and CPU flags, and the instruction pointer, a execution_context
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instance represents a specific point in the application's execution path. This is useful for building
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higher-level abstractions, like coroutines, cooperative threads (userland threads) or an equivalent to
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C# keyword yield in C++.
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A fiber provides the means to suspend the current execution path and to transfer execution control,
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thereby permitting another fiber to run on the current thread. This state full transfer mechanism
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enables a fiber to suspend execution from within nested functions and, later, to resume from where it
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was suspended. While the execution path represented by a fiber only runs on a single thread, it can be
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migrated to another thread at any given time.
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A context switch between threads requires system calls (involving the OS kernel), which can cost more than
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thousand CPU cycles on x86 CPUs. By contrast, transferring control among fibers requires only fewer than
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hundred CPU cycles because it does not involve system calls as it is done within a single thread.
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boost.context requires C++11!
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