CODEWITHSUNDEEP
matlabdebugginglogging
P i
P i

Reputation: 30734

Implementing a Debug-only Print-to-console in Matlab

I would like to set a flag that determines whether or not debug-print statements actually print to the console:

s_verbose       = 1;

global DBG
if s_verbose
    DBG = @(varargin) fprintf(varargin);
else
    DBG = @(varargin) 1;  % need the 1  :|
end

However this fails:

>> DBG('42')
Error using fprintf
Invalid file identifier.
Use fopen to generate a valid file identifier.

>> fprintf('42')
42

Is there any clean way to accomplish this?

Upvotes: 0

Views: 367

Answers (1)

Sam Roberts
Sam Roberts

Reputation: 24127

I often use a utility function like this:

function vfprintf(verbose, varargin)
% VFPRINTF Display output optionally depending on the level of verbosity.
%
% VFPRINTF(TF, ARGS) passes the arguments ARGS to the built-in MATLAB
% command |fprintf| if TF is logical true. If TF is logical false, VFPRINTF
% does nothing.

assert(islogical(verbose) && isscalar(verbose),...
    'utils:InvalidVerbose',...
    'VERBOSE must be logical true or false');

if verbose
    fprintf(varargin{:});
end

You can then call vfprintf instead of fprintf. Put your verbose variable as the first argument, with a value of true or false, and then follow with whatever arguments you would normally supply to fprintf. If verbose is true, it will display, but if verbose is false, it will do nothing.

PS - even if you do this, I would try to avoid making verbose a global variable if possible. It's not necessary.

Upvotes: 1

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