Bug in gcc 2.9.51 with -fpack-struct on Linux i386

[Martin v. Loewis]

> I think I found a bug in gcc 2.9.51 when compiling on i386 Linux. I
> first recognized it when a code sequence like

Thanks for your bug report. I could reproduce it with gcc-2.95.2; the
mainline compiler (2.96 19991202 (experimental)) seems to work fine.

Please note that -fpack-struct has undesired side effects, as it
applies to all structures - including those used by e.g. stdio, which
gives you an incompatibility with the Linux C library.

It is better to define packing on a structure-by-structure basis. If
you say

typedef struct{
    unsigned char a;
    unsigned short b;
    unsigned char c;
    unsigned short d;
    char e[3];
} __attribute__((packed)) SampleStruct ;
  
you declare that only the structure is packed; this works on 2.95.x as
well.

Regards,
Martin