Program Language Changes
 
The following items address changes in the various programming languages on
the Alpha system:
 
***
Ada
***
For performance reasons, the Ada Language aligns data on 4 byte boundaries.
While this is usually not a concern for users, it may cause problems when
dealing with structures.  The problem occurs because the system adds "filler"
bytes into the structure to align the data.  If your program relies on the
assumption that structures be stored contiguously in memory, you may need to
turn off this memory alignment "feature".
 
Contact MCIS for more information on turning off the memory alignment
"feature".
 
*****
BASIC
*****
BASIC is not currently available on the Alpha.  MCIS and Digital Equipment
Corp.
hope to make the BASIC compiler available during the summer of 1994.
 
Realize that programs previously written in BASIC can be converted to run on
the Alpha using the VEST command.
 
***
 C
***
The C compiler on the Alpha is considerably stricter than the C compiler on
the VAX.  The compiler rules can be releaxed by using the /STANDARD=VAXC
qualifier on the CC command.
 
For performance reasons, the C Compiler aligns data on 4 byte boundaries.
While this is usually not a concern for users, it may cause problems when
dealing with structures that contain char or short data types.  The problem
occurs because the system adds "filler" bytes into the structure to align the
data on 4 byte boundaries.  If your program relies on the assumption that
structures be stored contiguously in memory, you may need to turn off this
memory alignment "feature".  Use the /NOMEMBER_ALIGNMENT qualifier on the CC
command to turn off this "feature".  Realize that this qualifier will cause a
performance degradation in your program.
 
*****
COBOL
*****
COBOL on the Alpha does not check for invalid numeric data by default for
perforance reasons.  To enable this checking, compile the program with the
/CHECK=DECIMAL.
 
*******
Fortran
*******
MCIS is not aware of any significant changes in the Fortran compiler on the
Alpha system.
 
******
Pascal
******
For performance reasons, the Pascal Compiler aligns data on 4 byte
boundaries.  While this is usually not a concern for users, it may cause
problems when dealing with records that contain char or char array data
types.  The problem occurs because the system adds "filler" bytes into the
record to align the data on 4 byte boundaries.  If your program relies on
the assumption that structures be stored contiguously in memory, you may
need to turn off this memory alignment "feature".  Use the /ALIGN=VAX
qualifier on the PASCAL command to turn off this "feature".  Realize that
this qualifier will cause a performance degradation in your program.
 
**********
Questions?
**********
If you have any questions or concerns about the new Alpha system, please
contact MCIS at 529-7318 and ask for Patti Gregg.
 
--
                                     Kent Covert, Software Coordinator
                                     Miami Computing and Information Services
                                     Miami University, Oxford, OH
                                     [log in to unmask]  (internet)
                                     kacovert@miavx1                 (bitnet)