Function uart_irq_tx_complete 

pub unsafe extern "C" fn uart_irq_tx_complete(
    dev: *const device,
) -> i32

@brief Check if UART TX block finished transmission

@details Check if any outgoing data buffered in UART TX block was fully transmitted and TX block is idle. When this condition is true, UART device (or whole system) can be power off. Note that this function is not useful to check if UART TX can accept more data, use uart_irq_tx_ready() for that. This function must be called in a UART interrupt handler, or its result is undefined. Before calling this function in the interrupt handler, uart_irq_update() must be called once per the handler invocation.

@param dev UART device instance.

@retval 1 If nothing remains to be transmitted. @retval 0 If transmission is not completed. @retval -ENOSYS If this function is not implemented. @retval -ENOTSUP If API is not enabled.