Remove root level I/O zero initialization

Control generation of initialization code for root-level inports and outports set to zero

Model Configuration Pane: Code Generation / Optimization

Description

The Remove root level I/O zero initialization parameter specifies whether to generate initialization code for root-level inports and outports set to zero. This parameter does not apply to root-level inports and outports that you map to a service interface that uses the during-execution or outside-execution communication method.

Settings

on | off

On

Does not generate initialization code for root-level inports and outports set to zero.

During startup, standards-compliant C and C++ compilers initialize global data to zero, eliminating the need to include zero initialization code for this data in the generated code. Standards-compliant compilers do not necessarily initialize dynamically allocated data and local variables to zero. Before leaving the Remove root level I/O zero initialization parameter selected, confirm that your model meets these conditions:

• If your compiler is not standards-compliant, confirm that it initializes global data to zero.

• If you set the Code Interface packaging parameter to Reusable function, confirm that data is either statically allocated or that dynamically allocated data is initialized to zero.

Generated code initializes data that you specify in an Initialize Function block, even if you select this parameter.

Off

Generates initialization code for root-level inports and outports.

Generated code does not initialize data whose storage class has imported scope, unless you specify that data in an Initialize Function block. Generated code does not initialize inports that you connect to Initialize Function blocks. Generated code does not initialize data that you map to a service interface that uses the outside-execution or during-execution data communication methods.

If you set the Code interface packaging model configuration parameter to Nonreusable function, by default, the Remove root level I/O zero initialization check box is selected. At the command line, ZeroExternalMemoryAtStartup is set to off.

If you set the Code interface packaging parameter to Reusable function, by default, the Remove root level I/O zero initialization check box is cleared. At the command line, ZeroExternalMemoryAtStartup is set to on.

If you set the Code interface packaging parameter to C++ Class, the Remove root level I/O zero initialization check box is selected and cannot be changed. At the command line, ZeroExternalMemoryAtStartup is set to off.

If you set the Code interface packaging parameter to Reusable function and select the Use dynamic memory allocation for model initialization parameter, the Remove root level I/O zero initialization check box is cleared and ZeroExternalMemoryAtStartup is set to on.

Recommended Settings

Application	Setting
Debugging	No impact
Traceability	No impact
Efficiency	On (GUI), off (command line) (execution, ROM), No impact (RAM)
Safety precaution	No recommendation

Programmatic Use

Parameter: ZeroExternalMemoryAtStartup

Type: character vector

Value: 'off' (UI Setting On) | 'on' (UI Setting Off)

Default: 'off'

Version History

Introduced in R2007a