The storage for the answer area is provided by your program. For most requests, the answer area is optional. If provided, the answer area always contains a header record. Sometimes the header record is the only information stored in the answer area. If additional information is stored, the answer area header indicates where an array of data locator records can be found within the answer area. Depending on the request and the size of the answer area, zero or more data locator records are provided. Each entry in the data locator array identifies the location of an array of data records. These data records contain the functional output of the request. Both the data locators and the data records themselves are stored in the answer area. If the request is rejected, diagnostic data might be stored in the answer area header to provide detailed information about the failure. An answer area is optional for most requests, but desirable given the potential need for this detailed diagnostic data.

If the answer area provided by your program is not large enough to hold all of the relevant output data, the result will depend on the size of the answer area and the type of request.

• If an answer area is not provided for a request that requires one, the request is rejected.
• If the answer area is not large enough to hold the 64 byte header record, the request is rejected. No information is stored in the answer area. As appropriate, reissue the request with an answer area at least as long as the header record. Depending on the request, additional storage might be needed. Some requests require an answer area that is longer than the header record.
• If the answer area is smaller than the minimum size required for the request, the request is rejected. In this case, the minimum amount of answer area storage needed to process the request is stored in the answer area header. As appropriate, reissue the request with an answer area at least as long as the indicated minimum amount. Depending on the request, more storage might be desirable. For some requests, an answer area larger than the required minimum allows more information to be returned on each call, thus reducing the total number of calls that must be made to get all the data.
• If the answer area is smaller than the size needed to hold all of the available information, the request could complete with a return and reason code indicating that some of the data was stored in the answer area and that more information is available. In this case, the amount of answer area storage needed to get all of the available information is stored in the answer area header. As appropriate, reissue the request with an answer area at least as long as the indicated amount. For some requests, the amount of information can vary with the dynamics of the system. In such cases, an answer area larger than the indicated amount might be desirable so as to allow room for potential growth in the amount of information to be returned.
• If the answer area is smaller than the size needed to hold all of the available information, the request could complete with a return and reason code indicating that the request should be reissued to get the remaining data. In these cases, the request is intentionally designed for iterative execution. Each time the request is issued, XCF stores as much information as will fit in the provided answer area.