C/C++ Programmer's Guide (G06.25+)

Mixed-Language Programming for TNS/R and
TNS/E Native Programs
HP C/C++ Programmer’s Guide for NonStop Systems—429301-008
8-17
Considerations When Interfacing to pTAL
/* is more than one data declaring item */
/* in the block. */
int o = 'P' := [1, 2, 3]; extern short o [3] := {1, 2, 3};
int p; extern short p;
end block;
block b4;
/* Names are not changed because there */
/* is more than one data declaring item */
/* in the block. */
int q = 'P' := [1, 2, 3]; extern short q [3] := {1, 2, 3};
int .r [0:9]; extern short r [10];
end block;
block b5;
/* Names are not changed because there */
/* is more than one data declaring item */
/* in the block. */
int s = 'P' := [1, 2, 3]; extern short s [3] := {1, 2, 3};
int t = 'P' := [1, 2, 3]; extern short t [3] := {1, 2, 3};
end block;
block e;
/* Only one data declaring item. */
int u; extern short e;
int v = u;
end block;
If variable definitions are desired to be in the C++ source, remove the extern specifier
and change the pTAL source to ?NOEXPORTGLOBALS.
Parameters and Variables
This subsection gives guidelines for declaring compatible pTAL and C variables and
parameters. These guidelines supplement those given in Sharing Data on page 8-12.
The following topics are discussed:
•
STRING and char Variables
•
Arrays
•
Structures
•
Multidimensional Arrays
•
Arrays of Structures
•
Redefinitions and Unions
•
Pointers
•
Enumeration Variables
•
pTAL Routines as Parameters to C
•
C Routines as Parameters to pTAL
STRING and char Variables
pTAL STRING and C char simple variables each occupies one byte of a word. Share
variables of type pTAL STRING and C char by using pointers or declare both as int.
Arrays
pTAL and C arrays differ as follows: