Question

I am examining the value of a LPARAM when I receive the WM_KEYDOWN event. But I am unsure that I am correctly examining the 1st 16 bits then the next 8 bits & so on. This is how MSDN explains a LPARAM is organised for a WM_KEYDOWN msg: http://msdn.microsoft.com/en-us/library/ms646280(v=vs.85).aspx

Are my bit (splits?) correct?:

void outputLParam( LPARAM lParam )
{
    printf("Repeat Count        : %d\n", (lParam) & ((1L<<16)-1));          // print the value of the 1st 16 bits
    printf("Scan Code           : %d\n", (lParam >> 0x16) & ((1L<<8)-1));   // print the value of the next 8 bits
    printf("Extended Key        : %d\n", lParam & 0x24);                    // print the value of the next bit
    printf("Reserved            : %d\n", (lParam >> 0x25) & ((1L<<4)-1));   // print the value of the next 4 bits
    printf("Context             : %d\n", lParam & 0x29);                    // print the value of the next bit
    printf("Prev Key State      : %d\n", lParam & 0x30);                    // print the value of the next bit
    printf("Transition Key State: %d\n", lParam & 0x31);                    // print the value of the next bit
}

Answer 1

Here you go.

void outputLParam( LPARAM lParam )
{
    printf("Repeat Count        : %d\n", (lParam) & 0xFFFF);      // print the value of the 1st 16 bits
    printf("Scan Code           : %d\n", (lParam >> 16) & 0xFF);  // print the value of the next 8 bits
    printf("Extended Key        : %d\n", (lParam >> 24) & 0x1);   // print the value of the next bit
    printf("Reserved            : %d\n", (lParam >> 25) & 0xF));  // print the value of the next 4 bits
    printf("Context             : %d\n", (lParam >> 29) & 0x1);   // print the value of the next bit
    printf("Prev Key State      : %d\n", (lParam >> 30) & 0x1);   // print the value of the next bit
    printf("Transition Key State: %d\n", (lParam >> 31) & 0x1);   // print the value of the next bit
}