It's Clipper Version 5

>We've run into some problems locating exactly what data manager was used with, apparently, with files with a tlb extension. The following code snippet is some that's apparently used to access these files

>if SETUP->NFEET = 0 // use metric conv.
>  nstit := _sper3
>  nsper := setup->nsper
>endif
>fwindow( 6, 3, 15, 43, "GR+/RD,N/W,N", .t., "Executing Commands, "DOUBLE")

>Don't mean to be short on the sample, but if I were asked to describe the language, I'd say it looks like a cross between xBase, Pascal (note the assignment statements), and C (note the comments).
>
>My gut reaction is Clipper, but I've never laid eyes on line one of Clipper code, so I can't say for certain.
>
>tia,