INFO: #pragma pack() Affects Declarations, Not Definitions

• Microsoft C for MS-DOS, versions 6.0, 6.0a, 6.0ax
• Microsoft C/C++ for MS-DOS, version 7.0
• Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, 1.52
• Microsoft Visual C++, 32-bit Edition, version 1.0, 2.0, 2.1, 4.0, 5.0

SUMMARY

The pack pragma affects declarations, not definitions. Place #pragma pack() prior to data declarations.

MORE INFORMATION

Sample Code

The following program demonstrates usage of #pragma pack():

   /* compile options needed */
   /* Elements of variables of type struct x will be byte-aligned. */
   #pragma pack(1)
   struct x { int a; char b; int c; };

   /* Elements of variables of type struct y will be word-aligned. */
   #pragma pack(2)
   struct y { int a; char b; int d; };

   /* The pragma below does NOT affect the definitions that follow. */
   #pragma pack(4)

   struct x X;
   struct y Y;

   void main (void)
   { /* dummy main */ }

Keywords          : CLngIss
Version           : MS-DOS:6.0,6.00a,6.00ax,7.0; WINDOWS:1.0,1.5,1.51,1.52;  WINDOWS NT:1.0,2.0,2.1,4.0,5.0
Platform          : MS-DOS NT WINDOWS