How to determine CPU and memory consumption from inside a process?

Question

I once had the task of determining the following performance parameters from inside a running application:

• Total virtual memory available
• Virtual memo

Answer 1

in windows you can get cpu usage by code bellow:

#include 
#include 

    //------------------------------------------------------------------------------------------------------------------
    // Prototype(s)...
    //------------------------------------------------------------------------------------------------------------------
    CHAR cpuusage(void);

    //-----------------------------------------------------
    typedef BOOL ( __stdcall * pfnGetSystemTimes)( LPFILETIME lpIdleTime, LPFILETIME lpKernelTime, LPFILETIME lpUserTime );
    static pfnGetSystemTimes s_pfnGetSystemTimes = NULL;

    static HMODULE s_hKernel = NULL;
    //-----------------------------------------------------
    void GetSystemTimesAddress()
    {
        if( s_hKernel == NULL )
        {   
            s_hKernel = LoadLibrary( L"Kernel32.dll" );
            if( s_hKernel != NULL )
            {
                s_pfnGetSystemTimes = (pfnGetSystemTimes)GetProcAddress( s_hKernel, "GetSystemTimes" );
                if( s_pfnGetSystemTimes == NULL )
                {
                    FreeLibrary( s_hKernel ); s_hKernel = NULL;
                }
            }
        }
    }
    //----------------------------------------------------------------------------------------------------------------

    //----------------------------------------------------------------------------------------------------------------
    // cpuusage(void)
    // ==============
    // Return a CHAR value in the range 0 - 100 representing actual CPU usage in percent.
    //----------------------------------------------------------------------------------------------------------------
    CHAR cpuusage()
    {
        FILETIME               ft_sys_idle;
        FILETIME               ft_sys_kernel;
        FILETIME               ft_sys_user;

        ULARGE_INTEGER         ul_sys_idle;
        ULARGE_INTEGER         ul_sys_kernel;
        ULARGE_INTEGER         ul_sys_user;

        static ULARGE_INTEGER    ul_sys_idle_old;
        static ULARGE_INTEGER  ul_sys_kernel_old;
        static ULARGE_INTEGER  ul_sys_user_old;

        CHAR  usage = 0;

        // we cannot directly use GetSystemTimes on C language
        /* add this line :: pfnGetSystemTimes */
        s_pfnGetSystemTimes(&ft_sys_idle,    /* System idle time */
            &ft_sys_kernel,  /* system kernel time */
            &ft_sys_user);   /* System user time */

        CopyMemory(&ul_sys_idle  , &ft_sys_idle  , sizeof(FILETIME)); // Could been optimized away...
        CopyMemory(&ul_sys_kernel, &ft_sys_kernel, sizeof(FILETIME)); // Could been optimized away...
        CopyMemory(&ul_sys_user  , &ft_sys_user  , sizeof(FILETIME)); // Could been optimized away...

        usage  =
            (
            (
            (
            (
            (ul_sys_kernel.QuadPart - ul_sys_kernel_old.QuadPart)+
            (ul_sys_user.QuadPart   - ul_sys_user_old.QuadPart)
            )
            -
            (ul_sys_idle.QuadPart-ul_sys_idle_old.QuadPart)
            )
            *
            (100)
            )
            /
            (
            (ul_sys_kernel.QuadPart - ul_sys_kernel_old.QuadPart)+
            (ul_sys_user.QuadPart   - ul_sys_user_old.QuadPart)
            )
            );

        ul_sys_idle_old.QuadPart   = ul_sys_idle.QuadPart;
        ul_sys_user_old.QuadPart   = ul_sys_user.QuadPart;
        ul_sys_kernel_old.QuadPart = ul_sys_kernel.QuadPart;

        return usage;
    }
    //------------------------------------------------------------------------------------------------------------------
    // Entry point
    //------------------------------------------------------------------------------------------------------------------
    int main(void)
    {
        int n;
        GetSystemTimesAddress();
        for(n=0;n<20;n++)
        {
            printf("CPU Usage: %3d%%\r",cpuusage());
            Sleep(2000);
        }
        printf("\n");
        return 0;
    }