Does windows hid_write prepend a 0x00 report id?

[MicRaj]

I am trying to send HID reports with different report ids - my report id is the first byte in the buffer. On my device the report always comes through as report id 0x00. I am not getting this issue on linux.

int res;
uint8_t buffer[65] = {0}; 

buffer[0] = REPORT_ID_CUSTOM;        // Report ID (must be 1st byte)
buffer[1] = CMD_ADD;                 // Command
buffer[2] = data.modifier;           // First data byte
memcpy(&buffer[3], data.keycode, 6); // Remaining 6 data bytes

res = hid_write(handle, buffer, sizeof(buffer));```

[mcuee]

You may want to post more info about your device's HID report descriptors, hidapi version used, etc.

[MicRaj]

Yes ofcourse:
HID api version v0.15.0
My descriptor using usbview is as follows:

[Port4]  :  USB Composite Device


Is Port User Connectable:         yes
Is Port Debug Capable:            no
Companion Port Number:            0
Companion Hub Symbolic Link Name: 
Protocols Supported:
 USB 1.1:                         yes
 USB 2.0:                         yes
 USB 3.0:                         no

Device Power State:               PowerDeviceD0

       ---===>Device Information<===---
English product name: "Macropad"

ConnectionStatus:                  
Current Config Value:              0x01  -> Device Bus Speed: Full (is not SuperSpeed or higher capable)
Device Address:                    0x08
Open Pipes:                           3

          ===>Device Descriptor<===
bLength:                           0x12
bDescriptorType:                   0x01
bcdUSB:                          0x0200
bDeviceClass:                      0x00  -> This is an Interface Class Defined Device
bDeviceSubClass:                   0x00
bDeviceProtocol:                   0x00
bMaxPacketSize0:                   0x40 = (64) Bytes
idVendor:                        0xCAFE = Vendor ID not listed with USB.org
idProduct:                       0x400C
bcdDevice:                       0x0100
iManufacturer:                     0x01
     English (United States)  "MicRaj"
iProduct:                          0x02
     English (United States)  "Macropad"
iSerialNumber:                     0x03
     English (United States)  "503359276ACE359F"
bNumConfigurations:                0x01

          ---===>Open Pipes<===---

          ===>Endpoint Descriptor<===
bLength:                           0x07
bDescriptorType:                   0x05
bEndpointAddress:                  0x81  -> Direction: IN - EndpointID: 1
bmAttributes:                      0x03  -> Interrupt Transfer Type
wMaxPacketSize:                  0x0040 = 0x40 bytes
bInterval:                         0x05

          ===>Endpoint Descriptor<===
bLength:                           0x07
bDescriptorType:                   0x05
bEndpointAddress:                  0x02  -> Direction: OUT - EndpointID: 2
bmAttributes:                      0x03  -> Interrupt Transfer Type
wMaxPacketSize:                  0x0040 = 0x40 bytes
bInterval:                         0x0A

          ===>Endpoint Descriptor<===
bLength:                           0x07
bDescriptorType:                   0x05
bEndpointAddress:                  0x82  -> Direction: IN - EndpointID: 2
bmAttributes:                      0x03  -> Interrupt Transfer Type
wMaxPacketSize:                  0x0040 = 0x40 bytes
bInterval:                         0x0A

       ---===>Full Configuration Descriptor<===---

          ===>Configuration Descriptor<===
bLength:                           0x09
bDescriptorType:                   0x02
wTotalLength:                    0x0042  -> Validated
bNumInterfaces:                    0x02
bConfigurationValue:               0x01
iConfiguration:                    0x00
bmAttributes:                      0xA0  -> Bus Powered
  -> Remote Wakeup
MaxPower:                          0x32 = 100 mA

          ===>Interface Descriptor<===
bLength:                           0x09
bDescriptorType:                   0x04
bInterfaceNumber:                  0x00
bAlternateSetting:                 0x00
bNumEndpoints:                     0x01
bInterfaceClass:                   0x03  -> HID Interface Class
bInterfaceSubClass:                0x01
bInterfaceProtocol:                0x01
iInterface:                        0x00

          ===>HID Descriptor<===
bLength:                           0x09
bDescriptorType:                   0x21
bcdHID:                          0x0111
bCountryCode:                      0x00
bNumDescriptors:                   0x01
bDescriptorType:                   0x22 (Report Descriptor)
wDescriptorLength:               0x0043

          ===>Endpoint Descriptor<===
bLength:                           0x07
bDescriptorType:                   0x05
bEndpointAddress:                  0x81  -> Direction: IN - EndpointID: 1
bmAttributes:                      0x03  -> Interrupt Transfer Type
wMaxPacketSize:                  0x0040 = 0x40 bytes
bInterval:                         0x05

          ===>Interface Descriptor<===
bLength:                           0x09
bDescriptorType:                   0x04
bInterfaceNumber:                  0x01
bAlternateSetting:                 0x00
bNumEndpoints:                     0x02
bInterfaceClass:                   0x03  -> HID Interface Class
bInterfaceSubClass:                0x00
bInterfaceProtocol:                0x00
iInterface:                        0x00

          ===>HID Descriptor<===
bLength:                           0x09
bDescriptorType:                   0x21
bcdHID:                          0x0111
bCountryCode:                      0x00
bNumDescriptors:                   0x01
bDescriptorType:                   0x22 (Report Descriptor)
wDescriptorLength:               0x0024

          ===>Endpoint Descriptor<===
bLength:                           0x07
bDescriptorType:                   0x05
bEndpointAddress:                  0x02  -> Direction: OUT - EndpointID: 2
bmAttributes:                      0x03  -> Interrupt Transfer Type
wMaxPacketSize:                  0x0040 = 0x40 bytes
bInterval:                         0x0A

          ===>Endpoint Descriptor<===
bLength:                           0x07
bDescriptorType:                   0x05
bEndpointAddress:                  0x82  -> Direction: IN - EndpointID: 2
bmAttributes:                      0x03  -> Interrupt Transfer Type
wMaxPacketSize:                  0x0040 = 0x40 bytes
bInterval:                         0x0A

I have tried different buffersizes eg uint8_t buffer[64] = {0}; , uint8_t buffer[63] = {0}; but all of them seem to have a prepended 0x00 report id