How to build library written by C++ and use in iOS

Question

I now have to porting C++ code to iOS, trying to build static library by original C++ code and load the library on iOS. Because the original code is heavy, I start a small test to verify my steps could work or not.

First I need to build library (.a), which prints some string. I compile the following code and generate a library(.a) file

//talk.h
...
#include <iostream>
class Talk {
    Talk();
    void printHello();
    void printWord(char*);
};


//talk.cpp
#include "talk.h"
using namespace std;
void Talk::printHello() {
    cout << "Hello World";
}
void Talk::printWord(char* word) {
    cout << "Hello" << word;
}

The second step I try to do is open a new project for iOS app and then set link to the library file, also include corresponding "talk.h" header file. However, some errors happen on the header file even though I build library successfully.

The errors indicate that

1. "iostream" file not found
2. "Unknown type name 'class'; did you mean 'Class'?
3. any other errors...

I have try to rename controller.m to controller.mm, but it not fixes the problem

How to import the header file written in C++ for using library on iOS? Thanks

Answer 1

A rough outline:

In Xcode (starting with an either one of the template iOS Application projects (or an existing one):

• Create a new static library target: File -> New -> Target.... Select Framework Or Library, and then Cocoa Touch Static Library
• Add library source code: Drag library source code into Xcode project. In the dialog that appears, select the build target created above.
• Add project dependancy to library: Select Project in Project Navigation, the the iOS build target from Targets. Select Build Phases tab, then under Target Dependancies in the window, click on the + sign. A sheet opens (choose items to add) and the library target should be at thee top of the list.
• Include Library in iOS Target: Under Link Binary with Libraries, click +. The library (a .a file) should be at the top of the list.
• Link with libc++: As the step above. Select libc++ from the list.
• Enable Objective-C++ compilation for any source code file that needs to include the library headers by changing the extension from .m to .mm
• Build the iOS application target.

Xcode will have taken care of setting everything else up for you, including compiler flags and header search paths.