Obtaining I/O Buffers

The system will obtain the necessary buffers, but the application may obtain its own buffers with the GETPOOL macro. The application may issue the GETPOOL macro either before it opens the DCB or in the DCB Open exit. If the buffers supplied to Open processing are too small, the Open will fail with error code 35. Any application which obtains its own buffers MUST issue a FREEPOOL macro after it closes the DCB using the buffers. This frees the buffers which the GETPOOL macro obtained.