FreeMat

- Main Page
- Related Pages

ERROR Causes an Error Condition Raised

Section: Flow Control

# Usage

The `error` function causes an error condition (exception to be raised). The general syntax for its use is

       error(s),

where `s` is the string message describing the error. The `error` function is usually used in conjunction with `try` and `catch` to provide error handling. If the string `s`, then (to conform to the MATLAB API), `error` does nothing.

# Example

Here is a simple example of an `error` being issued by a function `evenoddtest`:

         evenoddtest.m

    function evenoddtest(n)
      if (n==0)
        error('zero is neither even nor odd');
      elseif ( n ~= fix(n) )
        error('expecting integer argument');
      end;
      if (n==int32(n/2)*2)
        printf('%d is even\n',n);
      else
        printf('%d is odd\n',n);
      end

The normal command line prompt `–>` simply prints the error that occured.

    --> evenoddtest(4)
    4 is even
    --> evenoddtest(5)
    5 is odd
    --> evenoddtest(0)
    In /home/sbasu/Devel/FreeMat4/doc/fragments/evenoddtest.m(evenoddtest) at line 3
        In scratch() at line 1
        In base(base)
        In base()
        In global()
    Error: zero is neither even nor odd
    --> evenoddtest(pi)
    In /home/sbasu/Devel/FreeMat4/doc/fragments/evenoddtest.m(evenoddtest) at line 5
        In scratch() at line 1
        In base(base)
        In base()
        In global()
    Error: expecting integer argument