Signature Parameter on the STRPGMEXP Command

The signature (SIGNATURE) parameter allows you to explicitly specify a signature for a service program. The explicit signature can be a hexadecimal string or a character string. You may want to consider explicitly specifying a signature for either of the following reasons:

The binder could generate a compatible signature that you do not want. A signature is based on the names of the specified exports and on their order. Therefore, if two export blocks have the same exports in the same order, they have the same signature. As the service program provider, you may know that the two interfaces are not compatible (because, for example, their parameter lists are different). In this case, you can explicitly specify a new signature instead of having the binder generate the compatible signature. If you do so, you create an incompatibility in your service program, forcing some or all clients to recompile.
The binder could generate an incompatible signature that you do not want. If two export blocks have different exports or a different order, they have different signatures. If, as the service program provider, you know that the two interfaces are really compatible (because, for example, a function name has changed but it is still the same function), you can explicitly specify the same signature as previously generated by the binder instead of having the binder generate an incompatible signature. If you specify the same signature, you maintain a compatibility in your service program, allowing your clients to use your service program without rebinding.

The default value for the signature parameter, *GEN, causes the binder to generate a signature from exported symbols.

You can determine the signature values for a service program by using the Display Service Program (DSPSRVPGM) command and specifying DETAIL(*SIGNATURE).