This pragma controls structure layout. The alignment of the structural elements in all structures is reduced to the number specified in the pragma. This has the effect of reducing the size of the structure. The scope of a pack pragma extends as far as the next pack pragma..
#pragma pack ([n])
n can be specified as a decimal, octal or hexadecimal number. The permitted values (in decimal notation) are 1, 2, 4 and 8.
Default value: 8
Attention!
Using pack pragmas has the effect of increasing run time since accessing unaligned structure elements takes longer than accessing aligned structure elements.
You should note that using the address of a structure element is not without risks. Attempting to access a structure element by using its address can cause a dump.