问题
I had to write some code for Arduino in C++. The code works perfectly, but wouldn't work in Arduino as I had used some libraries like vectors, ifstream, etc.
So I included the StandardCplusplus library. I downloaded the zip version of the library.
I copied the extracted version into the library folder of Arduino. Now the vector library works, i.e. it doesn't give any compile error.
But on #include fstream, Arduino gives the following error: fatal error: unistd.h: No such file or directory
回答1:
A bit late, but maybe someone else encounters the same problem, just like me looking for an answer couple of minutes ago. I turned the problem from an error to a warning by defining a symbol ARDUINO (I use eclipse, so I added a new symbol in the project's Properties --> C/C++ Build --> Settings --> AVR Compiler / AVR C++ Compiler --> Symbols. Don't know what you're using, but you could add -DARDUINO when calling avr-g++). The problem is in ios.cpp file, where you have:
#ifdef ARDUINO
#include <HardwareSerial.h>
#include <serstream>
#else
#include <fstream>
#endif
As soon as the ARDUINO symbol is seen in the ios.cpp file, two earlier includes are taken instead of the fstream.
来源：https://stackoverflow.com/questions/31921314/issues-with-standardcplusplus-library-in-arduino