我需要调用什么API才能使系统正常运行？

Question

我想从基于linux的系统上运行的C应用程序中获得系统正常运行时间。我不想调用uptime（1）并解析输出，我想调用我怀疑存在的基础C
API。任何人都知道是否有这样的电话，或者uptime（1）只是处理从wtmp获得的记录吗？

Answer 1

您要查找的系统调用是sysinfo（）。

它在sys / sysinfo.h中定义

它的签名是：int sysinfo（struct sysinfo * info）

从内核2.4开始，结构如下所示：

struct sysinfo {
    long uptime;             /* Seconds since boot */
    unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
    unsigned long totalram;  /* Total usable main memory size */
    unsigned long freeram;   /* Available memory size */
    unsigned long sharedram; /* Amount of shared memory */
    unsigned long bufferram; /* Memory used by buffers */
    unsigned long totalswap; /* Total swap space size */
    unsigned long freeswap;  /* swap space still available */
    unsigned short procs;    /* Number of current processes */
    unsigned long totalhigh; /* Total high memory size */
    unsigned long freehigh;  /* Available high memory size */
    unsigned int mem_unit;   /* Memory unit size in bytes */
    char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding for libc5 */
};

玩得开心！