See
TN035: Using Multiple Resource Files and Header Files with Visual C++[
^].
For your case you have to edit one of the
resource.h files, adjust the
_APS_NEXT_*
values on the bottom for new resources, and adjust all existing definitions to be before the NEXT definitions but after the definitions used so far plus space for new ones in the other file. See the above link for the allowed ranges in the section "Managing Symbols Shared by Multiple Visual C++-Edited .RC Files".
Note that VS will ask you to reload the file when editing it while the project is opened. Accept that or better edit the file when the corrresponding project is not opened.
[EDIT]
When multiple extension DLLs must be supported you should specify that the DLLs have to load resources using their
HMODULE
with
LoadResource()
and
HINSTANCE
with the other Load functions.
If the DLLs use MFC, they must get and store the current resource handle using
AfxGetResourceHandle()
, pass their handle to
AfxSetResourceHandle()
, and restore the setting after the resource has been loaded. See also
Extension DLLs[
^].
[/EDIT]