Do you mean CEERAN0 (Random Number Generator)?
If so, CEERAN0 is a procedure that is available as part of an ILE service program that is automatically bound to your program by the compiler. You don’t need to bind it specifically to your program.
Do a DSPPGM or DSPSRVPGM on your program/service program and you should find a number of system service programs bound in, such as QRNXIE, QLEAWI, etc. One of these will contain the CEERAN0 procedure.
A prototype for calling the API from RPG is:
* Generate a Random Number API
D CeeRan0 pr ExtProc(‘CEERAN0’)
D iSeed 10i 0
D iRandomNo 8f
D iFailCode 12a Options(*Omit)
All the best