These procedures provide a wrapper for the IBM QUSLFLD API. The service program procedures allow you to easily retrieve information about a file and its fields. The cp_uslfld /copy also includes extpgm prototypes for QUSLRCD and QUSLFLD. If you want to write your own calls to these APIs, you will need the data structures from QSYSINC.
NOTE: You will need to /copy rpgnextlib/qrpglesrc,cp_uslfld to use these procedures.