Why does one of my scanners show up as a camera when querying it with Windows Image Acquisition (WIA)?
I have two scanners connected to my machine via USB (An EPSON and an HP.) The Windows Scan and Fax utility seems confident that both devices are scanners, as expected. However, when I query WIA devices on my system and print their properties in a C++ program, the HP scanner is reported as a "Camera" type. The EPSON scanner is correctly reported as a Scanner.
Here is the output of several Device Information Properties from both devices:
Device ID: {6BDD1FC6-810F-11D0-BEC7-08002BE2092F}\0000
Vendor Description: EPSON
Device Description: EPSON DS-1630
Device Type: Scanner
Device Port Name: \\.\Usbscan1
Device Name: EPSON DS-1630
Device ID: {6BDD1FC6-810F-11D0-BEC7-08002BE2092F}\0001
Vendor Description: HP
Device Description: HP ENVY 5000 (USB)
Device Type: Camera
Device Port Name: \\.\Usbscan0
Device Name: HP ENVY 5000 (USB)
Below is the code I'm using to dump this information:
#include <Windows.h>
#include <stdio.h>
#include <wia.h>
int main(int argc, char **argv) {
argc;
argv;
HRESULT hr = CoInitialize(NULL);
if (FAILED(hr)) {
fprintf(stderr, "CoInitializeEx failed\n");
goto cleanup;
}
IWiaDevMgr2 *dev_mgmt;
hr = CoCreateInstance(CLSID_WiaDevMgr2, NULL, CLSCTX_LOCAL_SERVER,
IID_IWiaDevMgr2, (void **)&dev_mgmt);
if (FAILED(hr)) {
fprintf(stderr, "CoCreateInstance failed\n");
goto cleanup;
}
IEnumWIA_DEV_INFO *dev_info = NULL;
hr = dev_mgmt->EnumDeviceInfo(WIA_DEVINFO_ENUM_LOCAL, &dev_info);
if (FAILED(hr)) {
fprintf(stderr, "EnumDeviceInfo Failed\n");
dev_mgmt->Release();
goto cleanup;
}
while (hr == S_OK) {
IWiaPropertyStorage *prop_storage = NULL;
hr = dev_info->Next(1, &prop_storage, NULL);
if (FAILED(hr)) {
break;
}
if (hr == S_OK) {
PROPSPEC prop_spec[6] = {0};
PROPVARIANT prop_var[6] = {0};
const ULONG prop_count = sizeof(prop_spec) / sizeof(prop_spec[0]);
// Device ID, VT_BSTR
prop_spec[0].ulKind = PRSPEC_PROPID;
prop_spec[0].propid = WIA_DIP_DEV_ID;
// Vendor Description, VT_BSTR
prop_spec[1].ulKind = PRSPEC_PROPID;
prop_spec[1].propid = WIA_DIP_VEND_DESC;
// Device Description, VT_BSTR
prop_spec[2].ulKind = PRSPEC_PROPID;
prop_spec[2].propid = WIA_DIP_DEV_DESC;
// Device Type, VT_I4
prop_spec[3].ulKind = PRSPEC_PROPID;
prop_spec[3].propid = WIA_DIP_DEV_TYPE;
// Device Port Name, VT_BSTR
prop_spec[4].ulKind = PRSPEC_PROPID;
prop_spec[4].propid = WIA_DIP_PORT_NAME;
// Device Name, VT_BSTR
prop_spec[5].ulKind = PRSPEC_PROPID;
prop_spec[5].propid = WIA_DIP_DEV_NAME;
hr = prop_storage->ReadMultiple(prop_count, prop_spec, prop_var);
if (FAILED(hr)) {
fprintf(stderr, "prop_storage->ReadMultiple failed");
break;
}
fprintf(stderr, "\nDevice ID: %S\n", prop_var[0].bstrVal);
fprintf(stderr, "Vendor Description: %S\n", prop_var[1].bstrVal);
fprintf(stderr, "Device Description: %S\n", prop_var[2].bstrVal);
if (prop_var[3].iVal == 0x0000) {
fprintf(stderr, "Device Type: Default\n");
} else if (prop_var[3].iVal == 0x0001) {
fprintf(stderr, "Device Type: Scanner\n");
} else if (prop_var[3].iVal == 0x0002) {
fprintf(stderr, "Device Type: Camera\n");
} else if (prop_var[3].iVal == 0x0003) {
fprintf(stderr, "Device Type: Video\n");
} else {
fprintf(stderr, "Device Type: Unknown (%d)\n", prop_var[3].iVal);
}
fprintf(stderr, "Device Port Name: %S\n", prop_var[4].bstrVal);
fprintf(stderr, "Device Name: %S\n", prop_var[5].bstrVal);
FreePropVariantArray(prop_count, prop_var);
prop_storage->Release();
prop_storage = NULL;
}
}
dev_info->Release();
dev_mgmt->Release();
cleanup:
CoUninitialize();
}
Solution
I overlooked the fact that I needed to use the GET_STIDEVICE_TYPE macro to get the device type:
Use the GET_STIDEVICE_TYPE macro to get the device type. The device type and subtype are obtained from the INF file. An application reads this property to determine whether it is using a scanner, camera, or video device.
In which case they're now both a "Default" device type (Not quite sure what that means, however) and the devices have different SubTypes. This answers my initial question as to why it was showing up as a camera.
Device ID: {6BDD1FC6-810F-11D0-BEC7-08002BE2092F}\0000
Vendor Description: EPSON
Device Description: EPSON DS-1630
Device Type: Default (Type: 0x0000, SubType: 0x0001)
Device Port Name: \\.\Usbscan1
Device Name: EPSON DS-1630
Device ID: {6BDD1FC6-810F-11D0-BEC7-08002BE2092F}\0001
Vendor Description: HP
Device Description: HP ENVY 5000 (USB)
Device Type: Default (Type: 0x0000, SubType: 0x0002)
Device Port Name: \\.\Usbscan0
Device Name: HP ENVY 5000 (USB)
Updated code:
#include <Windows.h>
#include <stdio.h>
#include <sti.h>
#include <wia.h>
int main(int argc, char **argv) {
argc;
argv;
HRESULT hr = CoInitialize(NULL);
if (FAILED(hr)) {
fprintf(stderr, "CoInitializeEx failed\n");
goto cleanup;
}
IWiaDevMgr2 *dev_mgmt;
hr = CoCreateInstance(CLSID_WiaDevMgr2, NULL, CLSCTX_LOCAL_SERVER,
IID_IWiaDevMgr2, (void **)&dev_mgmt);
if (FAILED(hr)) {
fprintf(stderr, "CoCreateInstance failed\n");
goto cleanup;
}
IEnumWIA_DEV_INFO *dev_info = NULL;
hr = dev_mgmt->EnumDeviceInfo(WIA_DEVINFO_ENUM_LOCAL, &dev_info);
if (FAILED(hr)) {
fprintf(stderr, "EnumDeviceInfo Failed\n");
dev_mgmt->Release();
goto cleanup;
}
while (hr == S_OK) {
IWiaPropertyStorage *prop_storage = NULL;
hr = dev_info->Next(1, &prop_storage, NULL);
if (FAILED(hr)) {
break;
}
if (hr == S_OK) {
PROPSPEC prop_spec[6] = {0};
PROPVARIANT prop_var[6] = {0};
const ULONG prop_count = sizeof(prop_spec) / sizeof(prop_spec[0]);
// Device ID, VT_BSTR
prop_spec[0].ulKind = PRSPEC_PROPID;
prop_spec[0].propid = WIA_DIP_DEV_ID;
// Vendor Description, VT_BSTR
prop_spec[1].ulKind = PRSPEC_PROPID;
prop_spec[1].propid = WIA_DIP_VEND_DESC;
// Device Description, VT_BSTR
prop_spec[2].ulKind = PRSPEC_PROPID;
prop_spec[2].propid = WIA_DIP_DEV_DESC;
// Device Type, VT_I4
prop_spec[3].ulKind = PRSPEC_PROPID;
prop_spec[3].propid = WIA_DIP_DEV_TYPE;
// Device Port Name, VT_BSTR
prop_spec[4].ulKind = PRSPEC_PROPID;
prop_spec[4].propid = WIA_DIP_PORT_NAME;
// Device Name, VT_BSTR
prop_spec[5].ulKind = PRSPEC_PROPID;
prop_spec[5].propid = WIA_DIP_DEV_NAME;
hr = prop_storage->ReadMultiple(prop_count, prop_spec, prop_var);
if (FAILED(hr)) {
fprintf(stderr, "prop_storage->ReadMultiple failed");
break;
}
fprintf(stderr, "\nDevice ID: %S\n", prop_var[0].bstrVal);
fprintf(stderr, "Vendor Description: %S\n", prop_var[1].bstrVal);
fprintf(stderr, "Device Description: %S\n", prop_var[2].bstrVal);
fprintf(stderr, "Device Type: ");
if (GET_STIDEVICE_TYPE(prop_var[3].iVal) == 0x0000) {
fprintf(stderr, "Default ");
} else if (GET_STIDEVICE_TYPE(prop_var[3].iVal) == 0x0001) {
fprintf(stderr, "Scanner ");
} else if (GET_STIDEVICE_TYPE(prop_var[3].iVal) == 0x0002) {
fprintf(stderr, "Camera ");
} else if (GET_STIDEVICE_TYPE(prop_var[3].iVal) == 0x0003) {
fprintf(stderr, "Video ");
} else {
fprintf(stderr, "Unknown ");
}
fprintf(stderr, "(Type: 0x%04X, SubType: 0x%04X)\n",
GET_STIDEVICE_TYPE(prop_var[3].iVal),
GET_STIDEVICE_SUBTYPE(prop_var[3].iVal));
fprintf(stderr, "Device Port Name: %S\n", prop_var[4].bstrVal);
fprintf(stderr, "Device Name: %S\n", prop_var[5].bstrVal);
FreePropVariantArray(prop_count, prop_var);
prop_storage->Release();
prop_storage = NULL;
}
}
dev_info->Release();
dev_mgmt->Release();
cleanup:
CoUninitialize();
}
- Is difference between two pointers pointing to the same deallocated array well-defined in C?
- How to tell which C/C++ file is including a header that's causing compiler errors
- What are the various ways to disable and re-enable interrupts in STM32 microcontrollers in order to implement atomic access guards?
- Access a device's register using I²C
- What is '#' operator in C?
- How can I create an array of array of strings of varying lengths in C?
- How to generate an exact 1 µs interrupt on STM32F7xx using hardware timers
- Is there any way to get 64-bit time_t in 32-bit programs in Linux?
- Clang Analyser hints for tracking leaks
- Returning Deleted Rows in SQLite
- Creating a possibly unaligned pointer, but the location of the undefined behavior is not clear
- Better way to search for a node in binary tree
- Compile C files in C++ project which do not use precompiled header?
- Why can't we print ASCII values from 0 to 31?
- execute binary machine code from C
- What REALLY happens when you don't free after malloc before program termination?
- Program doesn't run after DFU
- When is pointer subtraction undefined in C?
- How is the initial value of x87 floating point control word defined?
- What's an object file in C?
- Portability of using union for conversion
- Visual Studio 2022 KMDF Driver Project "Build Succeeded" but No .sys File is Generated
- C puts() without newline
- How to check inf for AVX intrinsic __m256
- STM32F7 Discovery - USB FS host/device mode detection
- Can atomic operations of different sizes be mixed?
- Still reachable valgrind report when execve fails
- Function strcmp() doesn't find the match with the same values
- If bool is a macro for int, why is it a different size?
- how is _Bool implemented?