HP aC++/HP C A.06.28 Programmer's Guide Integrity servers (769150-001, March 2014)

The LOCALITY_ALL pragma specifies a name to be associated with the linker procedures and
global variables that should be grouped together at program binding or load time.
These are written to a relocatable object module. All procedures and global variables following
the LOCALITY_ALL pragma are associated with the name specified in the string.
VERSIONID
#pragma VERSIONID "string"
string is a string of characters that HP aC++ places in the object file.
The VERSIONID pragma specifies a version string to be associated with a particular piece of
code. The string is placed into the object file produced when the code is compiled.
For example, the directive
#pragma VERSIONID "Software Product, Version 12345.A.01.05"
places the characters Software Product, Version 12345.A.01.05 into the object file.
Data Alignment Pragmas
This section discusses the data alignment pragmas and their various arguments available on HP-UX
systems to control alignment across platforms.
ALIGN
#pragma align N
N is a number raised to the power of 2.
HP aC++ supports user-specified alignment for global data. The pragma takes effect on next
declaration. If the align pragma declaration is not in the global scope or if it is not a data
declaration, the compiler displays a warning message. If the specified alignment is less than the
original alignment of data, a warning message is displayed, and the pragma is ignored. Note
that for C code you must initialize the variables, otherwise the compiler will generate a warning.
#pragma align 2
char c; // "c" is at least aligned on 2 byte boundary.
#pragma align 64
int i, a[10]; // "i" and array "a" are at least aligned 64 byte boundary.
// the size of "a" is still 10*sizeof(int)
PACK
#pragma PACK [n]|[push|pop]|[,<name>][,n]|show]
n can be 1, 2, 4, 8, or 16 bytes. If n is not specified, maximum alignment is set to the default
value.
This file-scoped pragma allows you to specify the maximum alignment of class fields. The alignment
of the whole class is then computed as usual, to the alignment of the most aligned field in the class.
NOTE: The result of applying #pragma pack n to constructs other than class definitions
(including struct definitions) is undefined and not supported. For example:
#pragma pack 1
int global_var; // Undefined behavior: not a class definition
void foo() { // Also undefined
}
Example:
struct S1 {
char c1; // Offset 0, 3 bytes padding
98 Pragma Directives and Attributes