Saving and Restoring State :: Error Handling (Programming)

Programming

Saving and Restoring State

If you want to temporarily change the state of some warnings and then later return to your original settings, you can save the original state in a structure array and then restore it from that array. You can save and restore the state of all of your warnings or just one that you select with a message identifier.

To save the current warning state, assign the output of a warning control statement, as discussed in the last section, Output from Control Statements. The following statement saves the current state of all warnings in structure array s.

```
s = warning('query', 'all');
```

To restore state from s, use the syntax shown below. Note that the MATLAB function format (enclosing arguments in parentheses) is required.

```
warning(s)
```

Example 1 -- Performing an Explicit Query

Perform a query of all warnings to save the current state in structure array s.

```
s = warning('query', 'all');
```

Then, after doing some work that includes making changes to the state of some warnings, restore the original state of all warnings.

```
warning(s)
```

Example 2 -- Performing an Implicit Query

Turn on one particular warning, saving the previous state of this warning in s. Remember that this nonquery syntax (where state equals on or off) performs an implicit query prior to setting the new state.

s = warning('on', 'Control:parameterNotSymmetric');

Restore the state of that one warning when you are ready, with

```
warning(s)
```

Output from Control Statements Debug, Backtrace, and Verbose Modes