pub unsafe extern "C" fn PhidgetFrequencyCounter_setOnFrequencyChangeHandler(
ch: PhidgetFrequencyCounterHandle,
fptr: PhidgetFrequencyCounter_OnFrequencyChangeCallback,
ctx: *mut c_void,
) -> PhidgetReturnCodepub unsafe extern "C" fn PhidgetFrequencyCounter_setOnFrequencyChangeHandler(
ch: PhidgetFrequencyCounterHandle,
fptr: PhidgetFrequencyCounter_OnFrequencyChangeCallback,
ctx: *mut c_void,
) -> PhidgetReturnCode