Library confusion

Projects Programming
1

I added libraries nRF24LO1 and RF24-Master both from Zip Add Library

They went into an Aduino library folder in users.

The libraries work okay, however during compile before loading into arduino I get mystifying notices saying found multiple instances of nRF24LO1 when only 1 in library, and instances of RF24.

If I remove the libraries and // the #include lines then I get warning statements the files cannot be found.

I tried moving the two libraries to my C:/Program Files/Arduino/libraries and still get the warnings.

Appreciate to know why. Problem does not stop sketch working. Thanks

LIBRARY.jpg
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2

I think I may have found my own answer.

In the library folder RF24-Master there is a file nRF24LO1.h (4k size)

In the library folder nRF24LO1 there also is a file nRF24LO1.h (4k size)

Would they both be the same, allowing 1 to be removed?

Thanks

EDIT, Just tried removing but gave further errors. Would it be safe to ignore warnings as sketch seemed to work ok.

3

Just rearranged the order of library includes, all errors gone??

#include <printf.h>
#include <RF24.h>
#include <RF24_config.h>
#include <nRF24L01.h>

instead of

#include <nRF24L01.h>
#include <printf.h>
#include <RF24.h>
#include <RF24_config.h>

Must be a reason???

4

Those aren't errors. It's just some helpful information the Arduino IDE provides you. The reason is that when there are multiple library files with the same name the program tries to pick the right one but it might get it wrong so it's good to have a look at that information. In this case it appears that the correct nRF24L01.h file to use would have been the copy included with the RF24-Master library but it used the one from the nRF24L01 library instead. This sort of thing can cause confusing bugs some times and before the multiple libraries notification was added it was more difficult to spot what happened. It's likely that including RF24.h before nRF24L01.h causes the IDE to choose the correct one now.

5

Many thanks pert, good to have the reason explained. I only changed the order things were in by accident. So now I know, best regards