A small Windows utility that reads the MasterVolume of the default capture device (microphone) and shows a GUI message box if it is below 100%. It runs without opening a console window.

• Windows 10/11 (x64)
• Go 1.24+
• An enabled default capture device (microphone)

• github.com/moutend/go-wca
• github.com/go-ole/go-ole

They are already listed in go.mod. No manual go get is required.

• Using the batch script (GUI subsystem, no console window):
  • Run .\build_gui.bat to produce miclevel.exe.
• Using the command directly:
  • go build -ldflags="-H=windowsgui" -o miclevel.exe .

• Double-click miclevel.exe in Explorer or start it as a process.
• A warning message box is shown only if MasterVolume is below 100%.
• If MasterVolume is 100%, the app exits silently with no UI.

• Targets the default capture device with role EMultimedia.
• Reads the scalar volume (0.0–1.0) and treats values < 1.0 - 0.001 as "below 100%" (epsilon for floating-point).
• Since it is built as a GUI subsystem binary, fmt.Printf output is not visible. If you need logs, build without -H=windowsgui or write to a file.

• main_miclevel.go:
  • Initializes COM → gets default device → acquires IAudioEndpointVolume → reads volume → shows a MessageBoxW when needed.
• build_gui.bat:
  • Convenience script that runs go build -ldflags="-H=windowsgui" -o miclevel.exe ..

• The message box text is currently English. You can localize it by editing the strings passed to messageBox.