fatal error: functional: No such file or directory

[al3xsh]

Hi,

I'm trying to use your library with the Arduino Uno and I get the error message:

Arduino: 1.8.13 (Linux), Board: "Arduino Uno"

In file included from /home/alex/arduino_sketchbook/libraries/CoAP_simple_library/examples/coapserver/coapserver.ino:6:0:
/home/alex/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:26:10: fatal error: functional: No such file or directory
 #include <functional>
          ^~~~~~~~~~~~
compilation terminated.
exit status 1
Error compiling for board Arduino Uno.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Any ideas?

I feel like I must be missing something really obvious! :+1:

Regards,

Alex

[hirotakaster]

Hi @al3xsh , I did not get the "functional" error yet. Maybe you could compile after install the "ArduinoSTL" library .

[al3xsh]

Hi @hirotakaster,

Thanks for such a rapid reply!

I have tried installing ArduinoSTL from the libraries manager, then installing CoAP simple library, and then compiling the default coapserver example and I still get a message about missing during #include .

I have Coap simple library version 1.3.19 installed and ArduinoSTL version 1.1.0 installed.

Any other ideas?

Regards,

Alex

[hirotakaster]

It may not be an essential solution, but try to compile after install c++ to your Linux(apt install c++ or apt install g++).

[al3xsh]

Hi,

Thanks for the reply - I already have g++ installed (gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)).

I realised I wasn't including Arduino STL in the coaptest.ino code, so I've added #include at the very top of the file. However, now I get the error:

Arduino: 1.8.13 (Linux), Board: "Arduino Uno"

In file included from /tmp/arduino_modified_sketch_663275/coaptest.ino:8:0:
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:133:14: error: 'function' in namespace 'std' does not name a template type
 typedef std::function<void(CoapPacket &, IPAddress, int)> CoapCallback;
              ^~~~~~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:138:9: error: 'CoapCallback' does not name a type
         CoapCallback c[COAP_MAX_CALLBACK];
         ^~~~~~~~~~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:146:18: error: 'CoapCallback' has not been declared
         void add(CoapCallback call, String url) {
                  ^~~~~~~~~~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:160:9: error: 'CoapCallback' does not name a type
         CoapCallback find(String url) {
         ^~~~~~~~~~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h: In constructor 'CoapUri::CoapUri()':
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:143:17: error: 'c' was not declared in this scope
                 c[i] = NULL;
                 ^
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h: In member function 'void CoapUri::add(int, String)':
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:148:21: error: 'c' was not declared in this scope
                 if (c[i] != NULL && u[i].equals(url)) {
                     ^
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:153:21: error: 'c' was not declared in this scope
                 if (c[i] == NULL) {
                     ^
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h: At global scope:
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:170:9: error: 'CoapCallback' does not name a type
         CoapCallback resp;
         ^~~~~~~~~~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:183:23: error: 'CoapCallback' has not been declared
         void response(CoapCallback c) { resp = c; }
                       ^~~~~~~~~~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:185:21: error: 'CoapCallback' has not been declared
         void server(CoapCallback c, String url) { uri.add(c, url); }
                     ^~~~~~~~~~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h: In member function 'void Coap::response(int)':
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:183:41: error: 'resp' was not declared in this scope
         void response(CoapCallback c) { resp = c; }
                                         ^~~~
/home/alex/Dropbox/code/teaching/arduino_sketchbook/libraries/CoAP_simple_library/coap-simple.h:183:41: note: suggested alternative: 'frexp'
         void response(CoapCallback c) { resp = c; }
                                         ^~~~
                                         frexp
exit status 1
Error compiling for board Arduino Uno.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Any ideas?

Regards,

Alex

[al3xsh]

So looking into it a bit more - it seems ArduinoSTL doesn't yet support C++11 std::function.

https://github.com/mike-matera/ArduinoSTL/issues/45

I was wondering - have you had this library working with the Arduino Uno, or is it designed with the ESP8266 / ESP32 in mind?

It looks to me like this pull request:

https://github.com/hirotakaster/CoAP-simple-library/pull/18/commits/f6af4815ea5ab08b97dad339333d1e31ce0adf6e

might be the issue?

Regards,

Alex

[al3xsh]

Hi @hirotakaster ,

Last one from me :)

That was it - I reverted

typedef std::function<void(CoapPacket &, IPAddress, int)> CoapCallback;

to

typedef void (*CoapCallback)(CoapPacket &, IPAddress, int);

and the example now compiles for me.

I'll test that everything works properly when I get the chance, but it compiles with no errors so - for the moment at least - I'm happy!

Have a good weekend.

Regards,

Alex

p.s. if you're interested, once I've tested it I can send you a pull request with the fix.

[hirotakaster]

Hi @al3xsh , Oh, nice!! yes, this PR is hit to your error. https://github.com/hirotakaster/CoAP-simple-library/pull/18 So I think it's good for callback implementation to don't have to use ArduinoSTL.

Probably just this change. typedef void (*CoapCallback)(CoapPacket &, IPAddress, int);

If you okay, please send me pull request, I will merge it.

[al3xsh]

Hi @hirotakaster,

I've made the changes and added them to this pull request:

https://github.com/hirotakaster/CoAP-simple-library/pull/21

I also changed the COAP_BUF_MAX_SIZE to 128 so it works out of the box with the Arduino Uno - though this might be a bit small for some applications (?).

Regards,

Alex

[hirotakaster]

Hi @al3xsh , Thank you, I checked on Arduino Uno/ESP32 Dev/ESP8266, it works well.

[hirotakaster]

update and release https://github.com/hirotakaster/CoAP-simple-library/tree/1.3.20 You could use this version from Arduino library manager, thank you for your issue&pull request.