In data structure padding some allocate space is free this case is called is padding. Like a example is as as the structure we take three variable that is int,char,float. This is structure allocate 12 byte space. At the architecture of process it read 1 word at the time.(for 32 bit process 4 byte per word and for 64 bit process 8 byte per word).
struct emblogic
{ int; char;float}blog;
At this avoid this structure padding in C !
we used
#pragma pack(1)
After that the size of structure this structure is only 9 byte.
My question is where is define this pragma pack(1) (like as include directory path is /usr/include/ ). And how it works??