I've got a C program that has to read data from a file into a structure.
There seems to be some problem with the way the structure is stored in
memory.
The structure format is:
struct head {
char Type[2]; /* 2 bytes */
long Size; /* 4 bytes */
short Reserved1; /* 2 bytes */
short Reserved2; /* 2 bytes */
long Bits; /* 4 bytes */
};
Add that up, you get 14 bytes.
sizeof(struct head) reports 16 bytes.
Check of memory addresses reports:
Type[0]: bffffbb8
Type[1]: bffffbb9
Size: bffffbbc
Res1: bffffbc0
Res2: bffffbc2
Bits: bffffbc4
As you can see, the problem seems to be between Type and Size
There seems to be two extra bytes allocated, presumably as padding for
word boundaries or something like that. This of course is causing my
whole program to go haywire because two bytes are being read into nowhere.
I can read them with Type[2] and Type[3], but that is of no use to me as
they have to be the lsbs of Size. Size in turn gets two bytes that belong
to Res1 and so on.
How can I force the compiler to not pad to word boundaries?
Philip
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