Strings in C++ class file for Arduino not compiling

Question

I'm writing a stack class in C++ for an Arduino sketch. I believe it is fully compliant with the AVR (if that's what it's called; I can't remember exactly) compiler; I've used all malloc and free instead of new and delete and so on.

So I have a .h file with my class. I've imported it into the sketch, but when I try to compile, I get these errors:

In file included from sketch_may15a.cpp:1:
/CStack.h:58:18: error: string: No such file or directory
In file included from sketch_may15a.cpp:1:
CStack.h:61: error: variable or field 'Error' declared void
CStack.h:61: error: 'string' was not declared in this scope

And here are the first few lines for my class:

#include <string>
using namespace std;
void Error(string message) {

So the Arduino compiler can't find <string>, and the next few problems seem to relate to it (not sure what variable or field Error declared void means, my error function is just for debugging purposes).

I know Arduino sketches support strings without need for an import, but I'm not sure how that works out with C/C++/.h files. I've tried googling it, but there isn't much documentation.

Answer 1

Arduino sketches don't support any of the C++ standard library as they are compiled using avr-libc which doesn't support it. However, Arduino does provide the String class which should do what you need.

If you are writing a library you'll also need to #include <Arduino.h> (or #include <Wiring.h> if you are using a pre-1.0 version of the Arduino IDE).