Because both the size and the internal encoding of wchar_t are different between IAR Embedded Workbench for Arm version 7.xx and version 8.11 or later, the linker message “Warning [Lt009]: Inconsistent wchar_t size” will be generated when a library built with version 7.xx is used in version 8.11 or later.
In IAR Embedded Workbench for Arm version 7.80 and earlier, the size of wchar_t was two bytes and in version 8.11 the size of wchar_t is four bytes. Moreover the internal encoding of wchar_t objects between these versions objects is different.
This means that combining object files built with versions7.80 and 8.11 will generate a linker warning if the application uses wchar_t, the behavior will be unpredictable. In general, we strongly recommend using object code from one version only, and for a major upgrade such as 7.8 to 8.11, all code should be rebuilt.
If you choose to not to rebuilt, you should at least do following actions:
Note1: If you later add another 7.xx library to your 8.11(or later) project, please remove the suppress diagnostic option described above (“Lt009”) and go through steps a-c again.
A library that uses wchar_t built with IAR Embedded Workbench for Arm version 7.xx must be rebuilt to be used with version 8.11.