9.10.10 `packed`

The packed attribute specifies that a structure member should have the smallest possible alignment unless you specify a larger value with the aligned attribute.

Here is a structure in which the member x is packed, so that it immediately follows a, with no padding for alignment:

struct foo
{
  char a;
  int x[2] __attribute__ ((packed));
};

Note: PIC32A devices require that words be aligned on quad-byte boundaries. Care must be taken when using the packed attribute to avoid run-time addressing errors; for example, casting a pointer to an non-packed type may cause the compiler to generate code that will not correctly execute with misaligned data.

9.10.10 packed

9.10.10 `packed`