Uno- Debug. Code is being ignored in debug mode

1

When in debug mode, all if () statements, and int declarations are ignored. String declarations are executed.

If I use Serial.println() I can see these statements are executed.

I have created a demo program that uses conditional compilation to demonstrate the problem. Uncomment or comment out the line #define DEBUG 1 to see the problem.

Here is the code.

#include <Arduino.h>
#include <avr8-stub.h>

//*************************************
//  uncomment this line to run in debug mode.
//#define DEBUG 1
//************************************
void setup()
{
 #ifdef DEBUG
  debug_init();
#else
  Serial.begin(9600);
#endif
}

void loop()
{
// put your main code here, to run repeatedly:
#ifdef DEBUG
  breakpoint();
#endif
  String str = "This is a test";
  int x;
  x = 1;
  if (str != "")
  {
     x = 1;
#ifndef DEBUG
    Serial.println("Checked string if");
#endif
  }

  if (1 == 1 )
  {
    int x = 1;
#ifndef DEBUG
    Serial.println("Checked X IF");
#endif
  }
#ifndef DEBUG
  delay(3000);
#endif
}
2

grafik
grafik1024×768 56.9 KB

?

What does it show for you.

3

avrdude: verifying …
avrdude: 6766 bytes of flash verified

avrdude done. Thank you.

========================= [SUCCESS] Took 6.14 seconds =========================
Reading symbols from c:\Users\Colin\Documents\PlatformIO\Projects\Mill Controls V1.pio\build\uno\firmware.elf…
done.
PlatformIO Unified Debugger → Redirecting...
PlatformIO: debug_tool = avr-stub
PlatformIO: Initializing remote target…
loop () at src/main.cpp:22
22 String str = “This is a test”;
PlatformIO: Initialization completed
PlatformIO: Resume the execution to debug_init_break = tbreak main
PlatformIO: More configuration options → Redirecting...

Program received signal
SIGTRAP, Trace/breakpoint trap.
loop () at src/main.cpp:22
22 String str = “This is a test”;

Program received signal
SIGTRAP, Trace/breakpoint trap.
loop () at src/main.cpp:22
22 String str = “This is a test”;

Program received signal
SIGTRAP, Trace/breakpoint trap.
loop () at src/main.cpp:22
22 String str = “This is a test”;

4

image
image842×495 15.6 KB

This is in debug mode. In non-debug it runs as expected

5

The code may be so simple that is optimizes these simple assignments and 1 == 1 away with no further thought, especially since without DEBUG the calls to actual work-doing functions like Serial.println() is gone. Add

debug_build_flags = -O0 -g -ggdb3

to the platformio.ini and retry. Does it behave differently?

6

Yes that fixed it.

The original program it came out of was much more complex but did the same thing. What I was trying to do here was simply demonstrate the issue. I guess I was successful.

Thank you for the help.