HP MPE/iX 6.x Operating System manual 48

Figure 1-11. HP FORTRAN 77/iX COMMON Block Data Alignment Example

Native alignmen t for some HP P ascal/iX, COBOL II/XL, and HP F ORTRAN 77/iX data types is di￿erent than that used by languages running on MPE V/E. F or tables comparing alignmen t by data type, refer to Introduction to MPE/iX for MPE V Pr ogrammers (30367-90005).

If an application uses both nativ e aligned data ￿les and MPE V/E aligned data ￿les, an alignment directive should be speci￿ed in the program record de￿nitions to force MPE/iX or MPE V/E-aligned records on a structure-b y-structure basis. MPE/iX compilers o￿er t wo directives to specify MPE/iX or MPE V/E alignmen t, HP3000 _32 and HP3000 _16. For more information on these directiv es, refer to the programmer's guide for the appropriate language in the Language Series .

Note	The HP3000 _16 compiler directiv e maintains data alignmen t and format
	compatibility with MPE V/E and impacts the abilit y to use Native Mode
	(NM) data structures. Unless speci￿ed otherwise, all data elemen ts are in the
	mode of the program or as speci￿ed b y the compiler options in e￿ect.
	For example, to main tain Compatibilit y Mode (CM) data alignmen t and
	format and create NM data structures, y ou should explicitly de￿ne the
	individual structures to be in NM format as HP3000 _32 while operating
	under the HP3000 _16 compiler directiv e. The other alternativ e is to create a
	program that will read data in one mode and write it in the other.

Native Mode (NM) w ords and integers are di￿eren t from Compatibilit y Mode (CM) words. Table 1-1 shows the proper con versions. In this man ual, NM words are implied, unless a CM pre￿x is added to a term.

1-30 OVERVIEW