When you select "Extract translations to template" from
windows explorer, you see a configuration dialog where
you can specify file extensions to be treated.
I included "*.h" on the list of File Masks and I've got
the following message for each .H file:
WARNING: Unknown file extension .H. Reading file as
being pascal source.
The header filemask (*.h) should be redirected to
xgettext, because they are part o C/C++ source code.
These are the extensions that are normally associated
*.c *.cpp *.h *.hpp *.cc