Packing structures with gcc

Packing structures with gcc

[Robert Rati]

Hi all

I am trying to read a byte stream into a structure and padding shifts
the members of the structure. How do I turn on packing of the structures
to ensure no padding. I am working with gcc version 2.95.3 on a Linux
ppc distribution with 2.2.13 kernel and glibc 2.1.3.  I have tried using
the -fpack-struct option with no luck.  Are there options to the
standard binary distributions of gcc for struct packing, or do I need to
compile gcc from source?  I have tried compiling gcc 2.95.3 with compile
version 2.95.3 and I get an internal compiler error.  Upon looking at
the gcc source, it appears that HANDLE_SYSV_PRAGMA needs to be defined
(according to c-pragma.h), but how would I configure the makefiles in
the gcc source to enable this option correctly?  Would appreciate any
help with this.

Thanks
Rob

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Re: Packing structures with gcc

[David Edelsohn]

	Have you looked at the "__attribute__ ((packed))" functionality in
the GCC documentation under C Extensions -- Variable Attributes?  That
should allow you to pack the members of the structure when it is
declared.

David

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