The second parameter is the CDX file name, not the alias of the table
try
use myTable alias myAliasName in 0
? Sys(14, TagNo('myKeyName', Forceext(Dbf('myAliasName'), 'CDX'), 'myAliasName'))
"The five senses obstruct or deform the apprehension of reality."
Jorge L. Borges?
"Premature optimization is the root of all evil in programming."
Donald Knuth, repeating C. A. R. Hoare
"To die for a religion is easier than to live it absolutely"
Jorge L. Borges
