To provide addressability to an address/data space, a program might pass an ALET to another program. MVS™ allows your program to pass the following ALETs:

• An ALET of zero.
• An ALET that indexes into a public entry on a DU-AL, if the program that passes the ALET and the program that receives the ALET run under the same TCB or SRB (that is, they have the same DU-AL).
• An ALET that indexes into the PASN-AL, if the program that passes the ALET and the program that receives the ALET run in the same address space (that is, they have the same PASN-AL).
• An ALET that indexes into the PASN-AL for a SCOPE=COMMON data space.

Do not pass the following ALETs:

• An ALET of one across a space-switching PC linkage. (A space-switching PC instruction changes the program's secondary address space.)
• An ALET that indexes an entry on the PASN-AL, passed to a program in another address space, unless the ALET is for a SCOPE=COMMON data space. Each address space has its own PASN-AL.
• An ALET that indexes an entry on another task's DU-AL. (Each task has its own DU-AL). However, your program can pass such an ALET to a subtask if the subtask was created using the ALCOPY parameter on the ATTACH or ATTACHX macro; the ALET must have been valid at the time of the attach.
• An ALET that indexes a private entry, passed across an interface (through a PC instruction) that changes the EAX. (This rule is described in EAX-authority to an address space.)