MATLAB: How to obtain a warning message

MATLABwarning

I would like to extract the warning message, that a function throws. For example
syms x
solve(sin(1/sqrt(x)))
generates the warning:
Warning: The solutions are parametrized by the symbols:
k = Z_
I want to put the message to a variable programmatically. How can I make this? Thanks.
P.s. I know about lastwarn but I need to handle several warnings not just the last one.

Best Answer

As you found out already, lastwarn contains the last message only. You could overload the function warning to create a history of messages:
function varargout = warning(varargin)
persistent MsgList
if isa(MsgList, 'double')
  MsgList = {};
end
if nargin == 2 && isempty(varargin{1}) && isa(varargin{1}, 'double')
switch varargin{2}
  case 'GetList'
    varargout{1} = MsgList;
    return;
  case 'ResetList'
    MsgList = {};
    return;
end  % No OTHERWISE!
varargout = cell(1, nargout);
[varargout{:}] = builtin('warning', varargin{:});
MsgList{length(MsgList) + 1} = lastwarn;
This adds new messages for commands like warning('off', 'backtrace') also, so much more details are required for a smart behavior. But this demonstrates the general idea.
[EDITED] I've replaced the method to obtain and clear the list of messages. Using a magic string method in the first input is not 100% clean. Now this is used for controlling:
warning([], 'GetList')
warning([], 'ClearList')
Although it is very unlikely that somebody uses the warning message '$GetList', it might be a trap
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