Subject Re: Grid search From Mervyn Bick <invalid@invalid.invalid> Date Mon, 28 Sep 2020 15:15:31 +0200 Newsgroups dbase.getting-started On 2020/09/28 11:14, Robbie Nott wrote: > Hi Mervyn > > The EXTERN is a mysterious and scary thing for me. > I'm in awe of the code you sent, looks like another > language altogether ! > I know it's hooking into Windows DLL's and functions > > Would love to learn more about it > Will have a look at Ken's books and see if it's in there Ken devotes a complete chapter to the WIndows API and EXTERN in his dBASE book. The CALLBACK command, which was introduce in dBASE Plus 8, is covered in the dBASE Book Plus although Ken doesn't go into too much detail there. dBASE comes with over 2000 pre-defined EXTERN prototypes.  You will find them in C:\Program Files (x86)\dBASE\dBASE2019\Include\win32api.prg if you are using 64-bit Windows or C:\Program Files\dBASE\dBASE2019\Include\win32api.prg if you are using 32-bit Windows Unfortunately you will need to spend a LOT of time with Google to find out what each one does.  Programmers using C# or C++ use the API calls regularly.  Those dBASE programmers who also "speak" C tend to be the ones who fall back on the API functions when dBASE falls short.  Over the years the same few API methods have appeared in various examples with, very occasionally, a new one popping up. Every time I see a new API call I spend time following leads in the MSDN so that I can better understand why the API has been used.  It has got to the stage where I am now comfortable using these same API calls in my own code.  There are, however, probably still 2000 odd API calls that I still need to get to. :-) > > Perhaps I can get Windows to do more in future > I do have a client who runs Windows scripts from his program > Can dBase do this too ? I've never tried it and it may depend on what is in the scripts but the following line should allow you to do this. oWsh = new OleAutoClient( "WScript.Shell" ) Now oWsh.method() in your code will execute the argument to the method. Mervyn.