Using method from class in another .h file in c++

Question

I'm new in C++, and have been given a (relatively) complex piece of code.

I want to call a function transmit() from a .h file in another .c file. The transmit() is in the file serviceUart.hpp which content looks like this:

serviceUart.hpp

class ServiceUart
{
public:
    ServiceUart();
  void ioConfig(); // sets io HW ports and pins. Only needed at first boot
    void ioInit(); //
    bool readTrigger();
    bool detectConnection() {return (m_rxPin.get()|| m_enabled);}
    bool startup();
    bool transmit(const char* s, uint16_t length, bool wait = false);

The file drvr.cpp is where I try calling the function. A snippet of what I think is relevant from that file looks like this:

drvr.cpp

#include "EHS5_drv.hpp"

char debug[] = "I got to here!";
transmit(debug,true);

I tried serviceUart.transmit and serviceUart::transmit, but no matter what I try, I get the error code `#20 identifier "transmit" is undefined". I guess I'm misunderstanding the syntax?

To call a method you need an object of the class ServiceUart, I would suggest a good C++ book if this is a new concept to you. — Hatted Rooster
– Hatted Rooster, Commented Feb 28, 2019 at 13:13
Do you have a ServiceUart object instantiated? And note that you pass true for the length argument (and since you don't have such an overload, this is my guess as to the problem). Please edit your question to include the full and complete build output, copy-pasted as text. — Some programmer dude
– Some programmer dude, Commented Feb 28, 2019 at 13:14
I recognize by these comments, that I need to study more before posting. I will take @drescherjm 's proposal to heart. Im also new on SO. Should I delete the question, or can someone "shut it down" for me? Thanks for the comments. — Martin Rasmussen
– Martin Rasmussen, Commented Feb 28, 2019 at 13:21
@MartinRasmussen No need to do anything - you asked a question, you got your answer. This is how it's supposed to work. You might want to accept the answer which you like the most in order to mark your question answered. — anatolyg
– anatolyg, Commented Feb 28, 2019 at 16:31

Gor Asatryan · Accepted Answer · 2019-04-12 07:58:47Z

2

Method bool transmit(const char* s, uint16_t length, bool wait = false); is defined in ServiceUart. You have to create an object of ServiceUart class and then call method transmit()

char debug[] = "I got to here!";

ServiceUart obj;
obj.transmit(debug,true);

Or with new

ServiceUart* obj = new ServiceUart();
obj->transmit(debug,true);
delete obj;

Don't forget to delete obj.

edited Apr 12, 2019 at 7:58

answered Feb 28, 2019 at 13:33

Gor Asatryan

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1 Comment

Hemil Over a year ago

You might want to put the normal object first and then the new example. Because the person is new, and God forbid if he comes from Java, Java and C++ behave are different in a hell lot of ways

Hemil · Accepted Answer · 2019-02-28 16:12:31Z

2

You probably want:

char[] debug = "I got here";

ServiceUart serviceObg;
obj.transmit(debug, true);

answered Feb 28, 2019 at 16:12

Hemil

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