SQL/MP Programming Manual for C

HP NonStop SQL/MP Programming Manual for C—429847-008
D-1
D Converting C Programs
A C program developed for NonStop SQL/MP version 1 or version 2 software can run
on SQL/MP version 300 (or later) software without any changes to its embedded SQL
statements or directives. However, to use new SQL features, you must modify and
recompile the program.
Topics include:

Generating SQL Data Structures

Generating SQLDA Structures on page D-2

Planning for Future PVUs on page D-8
Generating SQL Data Structures
The SQLCA, SQLSA, and SQLDA data structures can change in future PVUs of
NonStop SQL/MP. Follow these guidelines if you are converting an existing C program
(that is, a program that uses version 1 or version 2 structures) or writing a new
program to use version 300 (or later) SQL structures:

Use the INCLUDE STRUCTURES directive to specify the version of the SQL
structures, even if you require version 1 or version 2 structures. To generate
version 300 or later structures, you must use the INCLUDE STRUCTURES
directive. For more information, see Section 9, Error and Status Reporting
.

If you allocate SQL data structures at run time, use the compiler-generated length
identifiers (for example, SQLSA_LEN for the length of an SQLSA structure) to
specify the memory to allocate. (In some cases, you can also use a C function to
generate the length of a structure.) Using the compiler-generated length identifiers
can reduce the impact on a program if the size of an SQL data structure changes
in a future PVU.

Use the system-generated eye-catcher identifiers to initialize the eye-catcher
fields. Do not hard code eye-catcher values or write code that depends on
hard-coded values. The eye-catcher values can change in a new PVU.

Use the SQLCAGETINFOLIST procedure to return information from the SQLCA
structure. Do not access this structure directly. HP reserves the right to change the
SQLCA structure in future PVUs.
Note. A D20 (or later) C compiler requires that a C program comply to the ISO/ANSI C
standard. For information about converting a program to follow this standard, see the C/C++
Programmer’s Guide.
Also, a C-series program can run at a low PIN on a D-series system without any changes.
However, for a C-series program to use D-series features (for example, to run at a high PIN),
you might need to convert certain parts of the program. For information about converting a
C-series program to use D-series features, see the Guardian Application Conversion Guide.