Hi!
I have a function that returns a boolean value, True of False. Is there any convention whether 0 = False or 0 = True?
It should be obvious, 0=False, 1=True. However programs usually return 0 on success and reserve higher numbers for error values. I.e. if the program finishes successfully (function int main() finishes successfully ), it returns 0 - and that contradicts that 0 should be false.

And especially if I want a function to do some computations on parameters passed by reference and return success status. Should it return 1 (true) for success, or should it return 0 for success - like any Unix program does?

Is there any convention for this?

The mix of conventions is a bit counter-intuitive, but the conventions are:

Program success = 0
Program other status = non zero

Within a program false = 0
Within a program true = non zero

Strict bool false = 0
Strict bool true = 1

Unfortunately, for function success/failure there is no well recognized convention.

How many different success values might you need? How many different failure values might you need? Someone apparently decided that for Unix program exit status only one success value was needed and multiple non success values.

If you only need one failure value, I find code a lot more readable if false is failure where tested by the calling function, so I prefer 0 as a fail code.