>What I need to measure i a character string that I read from a file.

I'm therefore going to assume that you are using low-level file functions to read the string, since you didn't say anything about a .dbf.

lnFileHandle=FOPEN("c:\myfile.txt")
IF lnFileHandle >= 0
lcString=FGETS(lnFileHandle, 10000)
lnLength=LEN(lcString) &&lnLength has string length
ENDIF

FGETS reads from the current pointer to the first carriage return or the nuber of bytes in the second argument, whichever comes first. LEN measures the length of the string that is returned.

Or am I missing the point completely? :)