Mixed project c and c++ -> possible?

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Mixed project c and c++ -> possible?

Postby stefanoxjx » Sat Mar 17, 2018 9:08 am

I've a library in cpp and some libs in c.
Exist a way to compile a mixed project?
I tried to rename the C files in cpp, but I'm submerged from errors.
For me, convert the cpp libs in C is very difficult, but convert C files in cpp is even more difficult.
The interested libs are espmqtt (writed in C) and this https://github.com/imxieyi/esp32-i2c-mpu6050 (writed in C++),



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Re: Mixed project c and c++ -> possible?

Postby kolban » Sat Mar 17, 2018 4:04 pm

To the best of my knowledge, you can freely mix C and C++ object files. A common problem is to realize that if you have a source file called a.cpp which define

Code: Select all

void aFunc() {
You can't simply call it from a source file called b.c as:

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extern void aFunc() {

void bFunc() {
Instead, you will have to define aFunc() as a C function with the following in a.cpp

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extern "C" void aFunc() {
Free book on ESP32 available here: https://leanpub.com/kolban-ESP32

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Re: Mixed project c and c++ -> possible?

Postby fly135 » Sat Mar 17, 2018 4:13 pm

Depends... If you want to call C code from C++, then no problem. Simply surround the C dot H includes with....

extern "C"
#include "myC.h"
#include "myotherC.h"

The other way around isn't practical. But if I say it can't be done then someone will come in and show how to do it. The exported names of C++ functions aren't the same as they appear. They are "mangled". Also C++ functions have the hidden "this" parameter. All of this makes calling C++ from C a problem.


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