assert_checkfalse Check that condition is false.

## Syntax

                flag = assert_checkfalse ( condition )
                flag = assert_checkfalse ( condition )
                [flag,errmsg] = assert_checkfalse ( condition )

## Parameters

condition:

  a matrix of booleans

flag :

  a 1-by-1 matrix of boolean, %t if condition is false, %f if not

errmsg :

  a 1-by-1 matrix of strings, the error message. If flag==%t, then errormsg=="". If flag==%f, then errmsg contains the error message.

## Description

Performs silently if all entries in `condition` are false.

Generates an error if any entry in `condition` is true. Generates an error if `condition` is not a boolean.

If any entry in condition is true,

- if the errmsg output variable is not used, an error is generated,

- if the errmsg output variable is used, no error is generated.

## Examples

    // Tests which pass
    assert_checkfalse ( %f );
    flag = assert_checkfalse ( %f )
    [flag,errmsg] = assert_checkfalse ( %f )
    [flag,errmsg] = assert_checkfalse ( [%f %f] );

    // Tests which fail
    assert_checkfalse ( [%t %f] );
    flag = assert_checkfalse ( [%t %f] )
    // No error generated
    [flag,errmsg] = assert_checkfalse ( [%t %f] )

    // Wrong calls
    assert_checkfalse ( "a" )

## History

5.4.0 Function introduced