Macros related to the platform
The following predefined macros are provided to facilitate porting applications between platforms. All platform-related predefined macros are unprotected and can be undefined or redefined without warning unless otherwise specified.
| Predefined macro name | Description | Predefined value | Predefined under the following conditions |
|---|---|---|---|
| __370__ | Indicates that the program is compiled or targeted to run on IBM® System/370. | 1 | Always predefined. |
| __HHW_370__ | Indicates that the host hardware is System/370. | 1 | Always predefined for z/OS®. |
| __HOS_MVS__ | Indicates that the host operating system is z/OS. | 1 | Always predefined for z/OS. |
| __MVS__ | Indicates that the host operating system is z/OS. | 1 | Always predefined for z/OS. |
| __THW_370__ | Indicates that the target hardware is System/370. | 1 | Always predefined for z/OS |
| __TOS_MVS__ | Indicates that the host operating system is z/OS. | 1 | Always predefined for z/OS. |