"Am I on a PEPPER?" runtime or compile-time checks?

plate-of-shrimp

Hello twiddlers and wigglers! Long type no typing.

Sometimes I have code that wants to work a little differently when the Bela is not mated to PEPPER.
That's actually true not just for C/C++ projects but Pd and probably Pyo Real Soon Now.
But let's consider what is probably the easiest case.

Is there a preprocessor macro, extern variable or function/method that returns whether you have compiled on or are running on PEPPER?

The sky is not falling; I can make the prospective user #define PEPPER which is where things are and is not really terrible.

bloop bleep cheers

giuliomoro

there's no built-in way of doing it, but you could resort to writing a file to disk (e.g.: in /root/boardcfg) and then read its content with ConfigUtils::readValue(). So you'd put something like IS_PEPPER=1 in that file if it is indeed a Pepper or IS_PEPPER=0 otherwise and then call

#include <MiscUtilities.h>
int gIsPepper;
...
// in setup()
if("1" == StringUtils::trim(ConfigFileUtils::readValue("/root/boardcfg", "IS_PEPPER")))
  gIsPepper =1;
else
  gIsPepper = 0;

or something like that

plate-of-shrimp

Gotcha, yep. Was looking at core/board_detect.cpp ie

static const std::map<std::string,BelaHw> belaHwMap = {
        {"NoHardware", BelaHw_NoHw},
        {"Bela", BelaHw_Bela},
        {"BelaMini", BelaHw_BelaMini},
        {"Salt", BelaHw_Salt},
        {"CtagFace", BelaHw_CtagFace},
        {"CtagBeast", BelaHw_CtagBeast},
        {"CtagFaceBela", BelaHw_CtagFaceBela},
        {"CtagBeastBela", BelaHw_CtagBeastBela},
        {"BelaMiniMultiAudio", BelaHw_BelaMiniMultiAudio},
        {"BelaMiniMultiTdm", BelaHw_BelaMiniMultiTdm},
        {"BelaMultiTdm", BelaHw_BelaMultiTdm},
        {"BelaMiniMultiI2s", BelaHw_BelaMiniMultiI2s},
        {"Batch", BelaHw_Batch},
};

and got to thinking, well, PEPPER isn't necessarily a "cape" in the Beaglebone sense, if it is a front panel that exposes I/O in a particular physical format, largely passively, such that you can't really know you're "wearing" a PEPPER.

I set an environment variable in my (root's) shell profile and can peek for it; that is already done for executables started from a shell. I just suppress it when the Bela is un-PEPPERed. It's pretty easy for other PEPPER people to add that. Pure Data may be where my choice fails, then your approach is the way.