> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/man/pthread/pthread_attr_affinity_np.3.md). # pthread\_attr\_affinity\_np.3 `pthread_attr_getaffinity_np` — 管理线程属性对象中的 CPU 亲和性 ## 名称 `pthread_attr_getaffinity_np`, `pthread_attr_setaffinity_np` ## 库 Lb libpthread ## 概要 `#include ` `Ft int Fn pthread_attr_getaffinity_np const pthread_attr_t *pattr size_t cpusetsize cpuset_t *cpusetp Ft int Fn pthread_attr_setaffinity_np pthread_attr_t *pattr size_t cpusetsize const cpuset_t *cpusetp` ## 描述 `Fn pthread_attr_getaffinity_np` 和 `Fn pthread_attr_setaffinity_np` 函数用于操作指定线程属性对象可用的 CPU 集合。 类型为 `Ft cpuset_t` 的掩码通过 `CPU_SET` 宏构成。如果用户提供的掩码不足以容纳所有匹配的 CPU，`Fn pthread_attr_getaffinity_np` 将失败并返回 Er ERANGE 。调用 `Fn pthread_attr_setaffinity_np` 时可接受任意大小的掩码，无限制。`Fn pthread_attr_setaffinity_np` 仅使用掩码的有效部分，其上界为系统中存在的最大 CPU id。如果为不存在的 CPU 设置了位，调用 `Fn pthread_attr_setaffinity_np` 将失败并返回 Er EINVAL 。 所提供的掩码大小应为 `cpusetsize` 字节。该大小通常通过调用 `sizeof(cpuset_t)` 获得，最终由以下文件中定义的 `CPU_SETSIZE` 值决定： `#include ` `Fn pthread_attr_getaffinity_np` 从 `pattr` 指定的线程属性对象中获取掩码，并将其存储到 `cpusetp` 提供的空间中。 `Fn pthread_attr_setaffinity_np` 将 `pattr` 指定的线程属性对象的掩码设置为 `cpusetp` 中的值。 ## 返回值 若成功，`Fn pthread_attr_getaffinity_np` 和 `Fn pthread_attr_setaffinity_np` 函数将返回零。否则将返回一个错误号以指示错误。 ## 错误 `Fn pthread_attr_getaffinity_np` 函数在以下情况下会失败： **\[Er** EINVAL] `pattr` 或其指定的属性为 `NULL`。 **\[Er** ERANGE] `cpusetsize` 过小。 `Fn pthread_attr_setaffinity_np` 函数在以下情况下会失败： **\[Er** EINVAL] `pattr` 或其指定的属性为 `NULL`。 **\[Er** EINVAL] `cpusetp` 指定了内核所支持集合之外的 CPU。 **\[Er** ENOMEM] 没有足够的内存来存储 cpuset 掩码。 ## 参见 cpuset(1), cpuset(2), cpuset\_getid(2), cpuset\_setid(2), pthread\_getaffinity\_np(3), [pthread\_np(3)](/man/pthread/pthread_np.3.md), pthread\_setaffinity\_np(3) ## 标准 `pthread_attr_getaffinity_np` 和 `pthread_attr_setaffinity_np` 函数是非标准的 FreeBSD 扩展，在其他操作系统上可能不可用。 ## 历史 `pthread_attr_getaffinity_np` 和 `pthread_attr_setaffinity_np` 函数首次出现于 FreeBSD 7.2。 ## 作者 `pthread_attr_getaffinity_np` 和 `pthread_attr_setaffinity_np` 函数由 David Xu 编写，本手册页由 Xin LI 编写。 --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://book.bsdcn.org/man/pthread/pthread_attr_affinity_np.3.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.