Get the name of a monitor - c++

Question

I'm having a bit of trouble retrieving the name of a monitor with winapi. According to other entries on stackoverflow, the correct way to get the name of a monitor is this:
EnumDisplayDevices(nullptr, 0, &oDisplayDevice, 0);
char lpszDeviceName[32];
memcpy(lpszDeviceName, oDisplayDevice.DeviceName, 32);
EnumDisplayDevices(lpszDeviceName, 0, &oDisplayDevice, 0);
char lpszMonitorName[128];
memcpy(lpszMonitorName, oDisplayDevice.DeviceString, 128);
However, EnumDisplayDevices returns FALSE the second time around. The first time around, DeviceName is \\DISPLAY1 and DeviceString is the GPU vendor. Using the MONITORINFOEX struct gives me the same value as DeviceName.
To be clear I'm looking for something like "Samsung blah blah," or what appears in the control panel on the screen resolution page.

Answer 1

This seems to return the proper data for me:
#include <Windows.h>
#include <iostream>
#include <string>
int main()
{
DISPLAY_DEVICE dd;
dd.cb = sizeof(dd);
int deviceIndex = 0;
while(EnumDisplayDevices(0, deviceIndex, &dd, 0))
{
std::string deviceName = dd.DeviceName;
int monitorIndex = 0;
while(EnumDisplayDevices(deviceName.c_str(), monitorIndex, &dd, 0))
{
std::cout << dd.DeviceName << ", " << dd.DeviceString << "\n";
++monitorIndex;
}
++deviceIndex;
}
return 0;
}
If you're compiling for UNICODE then use this instead:
#include <Windows.h>
#include <iostream>
#include <string>
int main()
{
DISPLAY_DEVICE dd;
dd.cb = sizeof(dd);
int deviceIndex = 0;
while(EnumDisplayDevices(0, deviceIndex, &dd, 0))
{
std::wstring deviceName = dd.DeviceName;
int monitorIndex = 0;
while(EnumDisplayDevices(deviceName.c_str(), monitorIndex, &dd, 0))
{
std::wcout << dd.DeviceName << L", " << dd.DeviceString << L"\n";
++monitorIndex;
}
++deviceIndex;
}
return 0;
}
Here's an example of the output:
\.\DISPLAY1\Monitor0, Dell U2410(DP)\.\DISPLAY2\Monitor0, Dell
2407WFP-HC (Digital)

Answer 2

This worked for me on Win10. "Retired Ninja" answer returned Generic PnP monitor.
Don't forget to add DEFINES += "WINVER=0x0601" or define that
#include <windows.h>
void QueryDisplay()
{
std::vector<DISPLAYCONFIG_PATH_INFO> paths;
std::vector<DISPLAYCONFIG_MODE_INFO> modes;
UINT32 flags = QDC_ONLY_ACTIVE_PATHS;
LONG isError = ERROR_INSUFFICIENT_BUFFER;
UINT32 pathCount, modeCount;
isError = GetDisplayConfigBufferSizes(flags, &pathCount, &modeCount);
if( isError )
{
return;
}
// Allocate the path and mode arrays
paths.resize(pathCount);
modes.resize(modeCount);
// Get all active paths and their modes
isError = QueryDisplayConfig(flags, &pathCount, paths.data(), &modeCount, modes.data(), nullptr);
// The function may have returned fewer paths/modes than estimated
paths.resize(pathCount);
modes.resize(modeCount);
if ( isError )
{
return;
}
// For each active path
int len = paths.size();
for( int i=0 ; i<len ; i++ )
{
// Find the target (monitor) friendly name
DISPLAYCONFIG_TARGET_DEVICE_NAME targetName = {};
targetName.header.adapterId = paths[i].targetInfo.adapterId;
targetName.header.id = paths[i].targetInfo.id;
targetName.header.type = DISPLAYCONFIG_DEVICE_INFO_GET_TARGET_NAME;
targetName.header.size = sizeof(targetName);
isError = DisplayConfigGetDeviceInfo(&targetName.header);
if( isError )
{
return;
}
QString mon_name = "Unknown";
if( targetName.flags.friendlyNameFromEdid )
{
mon_name = QString::fromStdWString(
targetName.monitorFriendlyDeviceName);
}
qDebug() << "Monitor " << mon_name;
}
}