Avoiding Pitfalls in Multi-Language Programming

ManualsBrandsHP ManualsSoftwareMPE/iX 6.5 Operating System

Subranges

0..255 ~BYTE NA unsigned char NA NA

0..65535 ~INTEGER*2 ~COMP 9(4) unsigned short ~SHORT INTEGER K(4) #3

NOTES:

#3 Integers may hold unsigned integer values

with the first bit being interpreted as a sign rather than

the larger unsigned magnitudes. Transact has 12-byte integer types

with no equivalents in other

languages.

#4 COMPLEX storage equivalent is two real numbers in a record/structure or two-element array. Only

Fortran supports COMPLEX arithmetic.

#5 C enum is always 4 bytes in size, Pascal enum can be 1,2,or 4 bytes.

#6 Basic uses PACK and UNPACK to create and

decompose structures/records to and from string

variables.

#7 Packed decimal data type is common to

Cobol, RPG, and Transact. Basic's DECIMAL data type is

not compatible with other languages. Zoned decimal data type is

also common to Cobol and

Transact.

Procedure Invocations

Pitfalls:

Procedure name case should be considered

carefully as some languages upshift, downshift, or are

case sensitive.

Procedure names which contain special characters (like underscore, hyphen, apostrophe) will

frequently require ALIASing to allow access from other languages.

Parameters may be passed by value, by

reference, or by descriptor, and the mode of parameter

passing differs by language.

Parameters other than the simple data types

may be difficult to construct and/or process in the

various languages.

Data alignment can be a problem; use SYNC in Cobol, avoid CRUNCHED in Pascal.

Hidden parameters can cause interfacing problems unless they are properly accounted for in the

procedure call.

Global and Common data may not be visible to routines written in other languages.

Recommendations:

Procedure names should be less than fifteen

characters in length, lowercase, with no special

characters.

Use simple data types whenever possible.

Avoid passing structures and arrays. Single dimension arrays of simple data types may be passed by

reference.

Page

Avoiding Pitfalls in Multi

Language Programming

7/18/2008

http://www.hp.com/cgi

bin/pf

new.cgi?IN=http://jazz.external.hp.com/papers/lang/pgm_pi

...