Differences in Using Packed Structures

The _Packed keyword tells the compiler to ignore the padding and pack the structure as much as possible.

In ILE C, this keyword can be used in a structure definition and type definition.

In ILE C++, the same keyword can be used only in a type definition.

typedef _Packed struct {
   .
   .
}ps_t;

_Packed struct {
   .
   .
}ps_v;

Therefore, you must make sure the _Packed keyword is used only in type definitions located in the header file.

In the ILE C/C++ compiler, the #pragma pack directive applies only to C programs. The ILE C #pragma pack directive is not compatible with the Windows #pragma pack directive.