Question

I am trying to list all devices attached to my system and after searching found this code which throws up error local function definations are illegal can someone explain what its means please.

Or is my issue because I am trying to use code that was from in C++. Thanks

WORKING CODE

#include <windows.h>
#include <setupapi.h>
#include <stdio.h>
#pragma comment(lib,"SetupAPI") 


void print_property
(
    __in HDEVINFO hDevInfo,
    __in SP_DEVINFO_DATA DeviceInfoData,
    __in PCWSTR Label,
    __in DWORD Property
)
{
    DWORD DataT;
    LPTSTR buffer = NULL;
    DWORD buffersize = 0;

    // 
    while (!SetupDiGetDeviceRegistryProperty(
                hDevInfo,
                &DeviceInfoData,
                Property,
                &DataT,
                (PBYTE)buffer,
                buffersize,
                &buffersize))
    {
        if (ERROR_INSUFFICIENT_BUFFER == GetLastError())
        {
            // Change the buffer size.
            if (buffer)
            {
                LocalFree(buffer);
            }
            // Double the size to avoid problems on 
            // W2k MBCS systems per KB 888609. 
            buffer = (LPTSTR)LocalAlloc(LPTR, buffersize * 2);
        }
        else
        {
            break;
        }
    }

    wprintf(L"%s %s\n",Label, buffer);

    if (buffer)
    {
        LocalFree(buffer);
    }
}



int main() 
{


    //int setupdi_version()
    //{
    HDEVINFO hDevInfo;
    SP_DEVINFO_DATA DeviceInfoData;
    DWORD i;

    // Create a HDEVINFO with all present devices.
    hDevInfo = SetupDiGetClassDevs(
        NULL,
        0, // Enumerator
        0,
        DIGCF_PRESENT | DIGCF_ALLCLASSES);

    if (INVALID_HANDLE_VALUE == hDevInfo)
    {
        // Insert error handling here.
        return 1;
    }

    // Enumerate through all devices in Set.

    DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA);

    for (i = 0; SetupDiEnumDeviceInfo(hDevInfo, i, &DeviceInfoData); i++)
    {
        LPTSTR buffer = NULL;
        DWORD buffersize = 0;

        print_property(hDevInfo, DeviceInfoData, L"Friendly name :", SPDRP_FRIENDLYNAME);

        while (!SetupDiGetDeviceInstanceId(
            hDevInfo, 
            &DeviceInfoData, 
            buffer, 
            buffersize, 
            &buffersize))
        {
            if (buffer)
            {
                LocalFree(buffer);
            }

            if (ERROR_INSUFFICIENT_BUFFER == GetLastError())
            {
                // Change the buffer size.
                // Double the size to avoid problems on
                // W2k MBCS systems per KB 888609.
                buffer = (LPTSTR)LocalAlloc(LPTR, buffersize * 2);
            }
            else
            {
                wprintf(L"error: could not get device instance id (0x%x)\n", GetLastError());
                break;
            }
        }

        if (buffer)
        {
            wprintf(L"\tDeviceInstanceId : %s\n", buffer);
        }

        print_property(hDevInfo, DeviceInfoData, L"\tClass :", SPDRP_CLASS);
        print_property(hDevInfo, DeviceInfoData, L"\tClass GUID :", SPDRP_CLASSGUID);
    }


    if (NO_ERROR != GetLastError() && ERROR_NO_MORE_ITEMS != GetLastError())
    {
        // Insert error handling here.
        return 1;
    }

    // Cleanup
    SetupDiDestroyDeviceInfoList(hDevInfo);

    system ("pause");

    return 0;

}

Answer 1

The code will compile and run if you comment out the following two lines as shown:

// int setupdi_version()
// {

I think the original code is from a function named setupdi_version() and it got mangled a bit when you tried to change it to main(). Note: it looks like the original source code is from here.

To answer your follow-on problem. Those are linker errors. You need to tell Visual Studio which .lib file(s) to link against. You can do that in the Visual Studio project dependencies or just add the following to the top of the source code.

#pragma comment(lib,"SetupAPI")