Scope of variables passed to function handles?

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Dehuan 2014-12-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/166859-scope-of-variables-passed-to-function-handles

评论： Dehuan 2014-12-16

采纳的回答： matt dash

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Hi, everyone,

I want to ask about the non-input variables in function handles.

For example, following code returns h(1)=2.

b=1;
h=@(a)a+b;
clear b;
display(sprintf('h(1)=%d', h(1)));

Is this kind of usage safe and correct?

Dehuan

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Answer 1

matt dash 2014-12-16

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https://ww2.mathworks.cn/matlabcentral/answers/166859-scope-of-variables-passed-to-function-handles#answer_162550

As far as i know, yes this is safe and correct. Any non-input variables pass their values to the function at the time the function handle was created. Subsequent changes to or clearing of those variables has no effect on the function.

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Adam 2014-12-16

Yes, this is correct. It is also why passing the handles structure, for example, in a GUIDE-based file to a callback is not a good idea, because a copy of the structure at the exact time the callback is set is hard-coded into the callback, irrespective of when it is called.

Dehuan 2014-12-16