RP2040_flash.ini uses
extern "C" {
#include <hardware/sync.h>
#include <hardware/flash.h>
};The SDK (on page 31) states:
The SDK has a C style API, however the SDK headers may be safely included from C++ code, and the functions called
(they are declared with C linkage).
Although it doesn't explicitly say that extern "C" is not required, I've always assumed it meant this and have never used extern "C" when including
the SDK headers. I've also built and run your example without extern "C" and it works fine.
On a separate subject (and perhaps somewhat cheekily) I thought I'd mention that I have written a "flash friendly" library for storing Key-Length-Value
records on flash memory. I think you'd find the implementation interesting, and you may even find it useful in one of your projects. It's at:
https://github.com/martinbudden/Library-FlashKLV
RP2040_flash.iniusesThe SDK (on page 31) states:
Although it doesn't explicitly say that
extern "C"is not required, I've always assumed it meant this and have never usedextern "C"when includingthe SDK headers. I've also built and run your example without
extern "C"and it works fine.On a separate subject (and perhaps somewhat cheekily) I thought I'd mention that I have written a "flash friendly" library for storing Key-Length-Value
records on flash memory. I think you'd find the implementation interesting, and you may even find it useful in one of your projects. It's at:
https://github.com/martinbudden/Library-FlashKLV