>>This is same as RUN /N7
>>
>>both does not wait for process completion?
>
>Honestly, I haven't used Run for many years, so I don't remember. Try it, it will open the program you specify as a normal program, without affecting VFP.

I'm using Shellexecute to show pdf and excel files. It simply runs application in parallel.
I need to get back signature created by OpenSsl .
Show I use

do while
  if file('signature.txt')
    exit
    endif
  enddo

to wait for completion ? I'm asking to better solution, just like RUN waits. If openssl.exe does not return signature, applications hangs.

WinAPI has CreateProcess and WaitForSingleObject for this, maybe they can called from VFP.
However this requires returning object in memory from CreateProcess