Please read the two wiki pages carefully in my first replies.
Here is a minimal sample, you save all the files, and then run cmd.exe
[[GetEditorManager().SaveAll();]] & cmd.exe
You might want to use SaveActive() instead of SaveAll(), so only the active editor gets saved.
I had to put a (sleep 1)before the exe-command, because sometimes the check for externally modified files does not kick in.
I think this happens because the saving might happen in the same second as the change by the external tool happens.
I don't know if there is such an easy command on windows or you need windows-scripting for it.
On linux I put [[ GetEditorManager().SaveActive(); ]] sleep 1 &&
before the executables name.
Windows 8.1 x64.
Tested there.
The following works for me (not tested with clang-format):
[[GetEditorManager().SaveActive();]] cmd.exe /c "timeout" "1" && "$(CODEBLOCKS)\sdk\LLVM\bin\clang-format.exe"