1 /* BEGIN Message Block Header include file */
 2 
 3 dcl  block_ptr ptr,                                         /* pointer to message block */
 4 
 5      1 ms_block_hdr aligned based(block_ptr),               /* message block header structure */
 6       2 f_offset bit(18) unaligned,                         /* offset to next block of message */
 7       2 first_block bit(1) unaligned,                       /* ON if block is first in message */
 8       2 block_count bit(17) unaligned;                      /* number of message bits in block */
 9 
10 /* END Message Block Header include file */