B.2.1 #pragma align

#pragma align integer(variable [,variable...])

Use align to make the listed variables memory-aligned to integer bytes, overriding the default. The following limitations apply:

• integer must be a power of 2 between 1 and 128; valid values are 1, 2, 4, 8, 16, 32, 64, and 128.

• variable is a global or static variable; it cannot be a local variable or a class member variable.

• If the specified alignment is smaller than the default, the default is used.

• The pragma line must appear before the declaration of the variables that it mentions; otherwise, it is ignored.

• Any variable mentioned on the pragma line but not declared in the code following the pragma line is ignored. Variables in the following example are properly declared.

#pragma align 64 (aninteger, astring, astruct)
int aninteger;
static char astring[256];
struct S {int a; char *b;} astruct;

When #pragma align is used inside a namespace, mangled names must be used. For example, in the following code, the #pragma align statement will have no effect. To correct the problem, replace a, b, and c in the #pragma align statement with their mangled names.

namespace foo {
    #pragma align 8 (a, b, c)
    static char a;
    static char b;
    static char c;
}