How to find out why Sloeber and Arduino IDE give different verify results.

[jantje]

If you find yourself in the situation that Sloeber has a different result from the Arduino IDE and there are no obvious reasons left on why; there is good news and bad news.

The good news is: There is a guaranteed way to find out why.
The bad news is: It is a tedious job that must be done very meticulous.

To understand why we need to understand the build a bit better.

How the Arduino build is done.

When Arduino IDE builds (called verify in Arduino IDE but the good old C/C++ name is build) a sketch (In Sloeber called a project) it actually start a bunch commands that run programs that are stored on your local machine.
Therefore if Sloeber runs the same commands Sloeber must end up with the same result.
In the Arduino IDE you can turn on verbose building in the preferences. If you turn "verbose printing" on and start a build you will see all the commands Arduino uses to build the sketch.
Sloeber is always in verbose mode. Sloeber shows all the commands in the console view.

How to compare the verbose output

By comparing the commands in the verbose output you can find the difference between Sloeber and Arduino IDE builds that may explain the issue at hand.
Before starting the compare there are some things to point out

• Arduino IDE does some preprocessing during the build; but the information added to the output make it quite clear when the actual build starts.
• Sloeber (and probably Arduino IDE more and more) does not always rebuild all the files all the time. So before starting a compare make sure you have verbose output of the full build. (In Sloeber delete the build folder to force a full build)
• Make sure you use as little files as possible that still contain the issue at hand
• Make 100% sure the same platform and platform version is used by Sloeber and the Arduino IDE (it is easy to miss this)
• Make 100% sure the same libraries and library versions are used by Sloeber and the Arduino IDE (it is easy to miss this)

Why is it hard?

Comparing 2 outputs that seems easy right? Well not so quick.
What comes to mind about what makes it hard are:

• There are many lines to compare.
• These lines can be extremely long (Windows says it is limited to 8191 and we think it is less but ESP easily hits that limit when Sloeber is not close to the root https://learn.microsoft.com/en-us/troubleshoot/windows-client/shell-experience/command-line-string-limitation )
• The tools are in a different location. When gcc is called it will be <Somewhere Arduino IDE installed this gcc>\gcc versus <Somewhere Sloeber installed this gcc>\gcc
• The files are in a different location. (same as above)
• The command line parameters will not be in the same order (and do not need to be)
• Sloeber adds additional parameters required by make
• A mix of / and \ (on windows)