Retrieving the width in a file:

A quick way to retrieve the width value in the printer file is to make up a small CL program and pass it the file name and library of your print file. In that CL program, execute the following command on your print file. Read that file in your CL program, and then return the values that you want to your calling program.
DSPFD FILE(QSYSPRT) TYPE(*ATR) OUTPUT(*OUTFILE) FILEATR(*PRTF) OUTFILE(QTEMP/QAFDPRT)