如何包含Linux头文件，例如linux/getcpu.h? [英] How do I include Linux header files like linux/getcpu.h?

问题描述

我正在使用 Linux 3.5.0-17-generic#28-Ubuntu SMP Tue Oct 9 19:31:23 UTC 2012 x86_64 GNU/Linux ，我需要#包括< linux/getcpu.h> .编译器抱怨找不到文件.linux的头文件在哪里?

解决方案

简短的回答:通常，您不直接包含这些标头.

其中的大多数OS/Machine特定标头都会自动包含在更通用的标头中.那些不是仅Linux功能，可能对于您正在运行的版本可用，也可能不可用.

关于 getcpu ，还有一个更标准化的版本，称为 sched_getcpu ，可在 sched.h 中找到，并且具有相同的功能./p>

或者，您还可以测试系统调用在您的系统上是否可用，然后手动调用它:

  #define _GNU_SOURCE#include< unistd.h>#include< sys/syscall.h>静态内联int getcpu(){#ifdef SYS_getcpuint cpu，状态；状态=系统调用(SYS_getcpu，& cpu，NULL，NULL);返回(状态== -1)?状态:cpu；#别的返回-1;//不可用#万一} 

如果syscall返回-1，则变量errno( #include< errno.h> )给出错误代码.

I'm using Linux 3.5.0-17-generic #28-Ubuntu SMP Tue Oct 9 19:31:23 UTC 2012 x86_64 GNU/Linux, and I need to #include<linux/getcpu.h>. The compiler complains that it cannot find the file. Where are the header files for linux?

解决方案

Short answer: usually, you don't include those headers directly.

Most OS/Machine specific headers in there are automatically included for you by a more general header. Those that are not are linux only features which may or may not be available for the version you are running.

As to getcpu, there is a more standardised version called sched_getcpu which is found in sched.h and has the same function.

Alternatively you can test wether that system call is available on your system and call it manually:

#define _GNU_SOURCE  
#include <unistd.h>
#include <sys/syscall.h>

static inline int getcpu() {
    #ifdef SYS_getcpu
    int cpu, status;
    status = syscall(SYS_getcpu, &cpu, NULL, NULL);
    return (status == -1) ? status : cpu;
    #else
    return -1; // unavailable
    #endif
}

The variable errno (#include <errno.h>) gives the error code, if syscall returns -1.

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