posix - 我如何确定是否是 POSIX 应用程序。在系统启动后 5 分钟内运行？

Question

来自 C++ 应用程序。为 AIX、HP-UX、Linux、OSX 和 Solaris 编译是否有一种简单的方法来确定应用程序是否可用。在系统启动后 5 分钟内运行？

在 Windows 上我可以这样做:

// return true if OS has recently booted up
bool at_os_boot_time()
{
    /*  GetTickCount() returns the number of miliseconds since system start.
        So "...the time will wrap around to zero if the system is run 
        continuously for 49.7 days" - so this function will erroneously 
        return true for a 5 minute period 49.7 days after boot */
    return ::GetTickCount() < 5 * 60 * 1000;
}

我找不到 Unix 世界中的等价物。

Answer 1

这是来自 linux 上的 kernel.h:

struct sysinfo;
extern int do_sysinfo(struct sysinfo *info);

#endif /* __KERNEL__ */

#define SI_LOAD_SHIFT   16
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 short pad;     /* explicit padding for m68k */
    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: libc5 uses this.. */
};