NET: can not add OUT pin .. it already has out pin

How net function should work? Why I can't connect one input to two outputs? or

Multiple in pins can be connected to an out, but only one out can ever be connected to a signal.

If for some reason you need to use more than one source for a signal, you can use an or2 or another hal logic component.
linuxcnc.org/docs/html/man/man9/or2.9.html

Example
Now the example you gave looks like it only has one output pin (axis.0.amp-enable-out) and two input pins, so it shouldn't be a problem. (I say this guessing that "driver.enable" is supposed to represent some GPIO input pin that sends a signal out to enable your drive, such as parport.0.pin-09-out.)

Don't get it. Once again - one pin is an input. This input is casted as a signal. This signal is transmitted to multiple output pins.
As it is written here: linuxcnc.org/docs/2.5/html/hal/basic_hal...#_net_a_id_sub_net_a This is my case, that prints error.

Maybe there is a missconception about input and output. I mean input as an input for net function.

That line of hal code should not give you any problems due to multiple out pins, as both of the parport pins you have there are both hal input pins. (It is a little confusing since in hal they receive the signal as an input that the parallel port sends out.)

If you are getting a fault because of something to do with that line, it is possible that signal name is used somewhere else in your hal file(s) where another output (or even possibly the same one) is connected to it.

It seems that any net connection that output is my driver's pin results in such error
exact line looks for example like that:

If you could post a copy of your whole hal file.

If you can run halrun and load your driver, then run show pin that will show the pins available from your driver and their directions.

No need to run a whole configuration.

Thanks, it started working
I used hal_pin_bit_newf(HAL_OUT not hal_pin_bit_newf(HAL_IN

So you zigged when you should have zagged ?

Glad you got it sorted