Struct packing and logistics
Hi,
I making a small C program that creates different objects in a window dependant on the data in an external file (A scripting system, if you like).
I made three structs, which have a parent-child relationship (one struct has a pointer to an array of the second struct which has a pointer to an array of the third struct >puff< >pant<). They are also stored in this way in the file.
After reading the first struct, allocating space for all of its child structs and reading them, I then come to allocating space for all the children of each of the 2nd structs, and reading them. The only thing is, reading the data directly from the disk into the whole struct seems to leave a byte of data out.
This doesn't happen, however, when each data is read into each individual member of the struct. Asking around produced the response "the struct is being packed to alignment in memory", and checking the Project Settings in MSVC shows an 8-byte boundary alignment. Struct 1 is 10 bytes long (hmm), struct 2 is 16 bytes long (no problems there) and struct 3 is 19 bytes long (ahh...)!
The question is, do I adjust the alignment to smaller boundaries ("degrading performance" as MSDN puts it), or add empty bytes to my files to retain alignment?
