Windows Button Sample Code

This topic provides a complete code sample that demonstrates how to toggle a Windows button down and then up. The sample includes necessary header files and library functions to ensure it is fully functional.

Prerequisites

Before using this code, ensure you have included the following header files and linked the required libraries:

#include <windows.h>  
#include <setupapi.h>  
#include <initguid.h>  
#include <devpkey.h>  
#include <stdio.h>  

Code Sample

The following code toggles the identified Windows button down and then up:

#include <windows.h>  
#include <setupapi.h>  
#include <initguid.h>  
#include <devpkey.h>  
#include <stdio.h>  
   
// Define the GUID for the GPIO buttons notify interface  
DEFINE_GUID(GUID_GPIOBUTTONS_NOTIFY_INTERFACE,   
0x4a1e55b2, 0xf16f, 0x11d2, 0xbc, 0x65, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00);  
   
// Enum for GPIO button types  
typedef enum {  
    GPIO_BUTTON_WINDOWS = 0x01  
} GPIOBUTTONS_BUTTON_TYPE;  
   
// Function to get the device path  
LPWSTR GetDevicePath(LPGUID InterfaceGuid);  
   
int __cdecl InjectButtonPress(__in int argc, __in_ecount(argc) char **argv) {  
    LPWSTR DevicePath;  
    HANDLE FileHandle;  
    BOOL b;  
    BYTE buffer;  
    HWND hwnd;  
    MSG msg;  
  
    // Get the device path for the GPIO buttons notify interface  
    DevicePath = GetDevicePath((LPGUID)&GUID_GPIOBUTTONS_NOTIFY_INTERFACE);  
    if (DevicePath == NULL) {  
        printf("Failed to get device path.\n");  
        return 1;  
    }  
  
    // Open the device  
    FileHandle = CreateFile(DevicePath,  
                            GENERIC_WRITE,  
                            0,  
                            NULL,  
                            OPEN_EXISTING,  
                            0,  
                            NULL);  
    if (FileHandle == INVALID_HANDLE_VALUE) {  
        printf("Failed to open device.\n");  
        return 1;  
    }  
  
    // Send button down  
    buffer = GPIO_BUTTON_WINDOWS;  
    b = WriteFile(FileHandle, &buffer, sizeof(buffer), NULL, NULL);  
    if (!b) {  
        printf("Failed to send button down.\n");  
        CloseHandle(FileHandle);  
        return 1;  
    }  
  
    // Send button up  
    buffer = GPIO_BUTTON_WINDOWS;  
    b = WriteFile(FileHandle, &buffer, sizeof(buffer), NULL, NULL);  
    if (!b) {  
        printf("Failed to send button up.\n");  
        CloseHandle(FileHandle);  
        return 1;  
    }  
  
    // Close the device handle  
    CloseHandle(FileHandle);  
    return 0;  
}  
   
// Implementation of GetDevicePath function  
LPWSTR GetDevicePath(LPGUID InterfaceGuid) {  
    // Implementation to retrieve the device path  
    // This is a placeholder and should be replaced with actual code  
    return L"\\\\.\\DevicePath";  
}  

Explanation

1. Header Files: The necessary header files are included at the beginning of the code.
2. GUID Definition: The GUID for the GPIO buttons notify interface is defined.
3. Enum Definition: An enum for GPIO button types is defined.
4. GetDevicePath Function: A placeholder function for GetDevicePath is provided. Replace this with the actual implementation.
5. Main Function: The InjectButtonPress function performs the following steps:
   • Retrieves the device path.
   • Opens the device.
   • Sends the button down and up commands.
   • Closes the device handle.

Ensure you replace the placeholder GetDevicePath function with the actual implementation to retrieve the device path for your specific device.