Chris--A
PrintEx conflicts with another library on ESP32?
I have a project that compiles just fine on avr and ESP8266, but not on ESP32. When I compile my project on ESP32 I get an error about redefining select?
/home/bakers/Arduino/libraries/PrintEx/src/lib/TypeTraits.h:78:55: error: 'template<bool V, class T, class U> struct select' redeclared as different kind of symbol
template< bool V, typename T, typename U > struct select { typedef U type; };
It's either from one of the core ESP32 IP libraries, or the ESP32 WebServer library. I don't know how to dig any deeper as the error message is a little beyond me. I'm glad to help test troubleshoot if you can tell me where to start.
After some digging I was able to recreate the error with the small test case.
#include <WiFi.h>
#include <PrintEx.h>
void setup() { }
void loop() { }
Setting your board to an ESP32 board and compiling this sketch will manifest the error.
Digging through the trace it looks like an include of an include of an include... Looks like maybe it's a conflict with this:
https://github.com/espressif/arduino-esp32/blob/master/tools/sdk/include/newlib/sys/select.h#L25
PrintEx declares select as a template, but this library has already declared it as an int?
As a temporary workaround you can wrap the include in its own namespace:
namespace printex {
#include <PrintEx.h>
}
printex::StreamEx serial = Serial;
I'm guessing at this point this library has been abandonned? Last commit was from 2016.
Seems like just commenting out the offending lines work fine: https://github.com/livello/PrintEx/commit/b430e1eb3a7a334d32464c669cf9b3df4c826c15