Unaligned and aligned structures

Paul Schauble Schauble at MIT-MULTICS.ARPA
Wed Jan 2 16:35:49 AEST 1985


The unaligned type modifier proposed by Joseph Yao already exists in
other languages.  It is, however, usually taken to be a property of the
structure rather than of an individual data type.  E.g.

          struct foo aligned {...

This is portable, even to machines that require alignment.  It just
demands that the compiler generate non-alignment dependant moves to/from
an aligned area.  This is what the programmer has to do when a truly
unaligned structure is needed.  !Better the machine do it than me!

Hay Committee...Unlike the recent proposal on decimal arithmetic, which
I feel does not fit the intent of C as an implementation language, this
one does fit.  I have frequently needed truly non-aligned structures to
communicate with hardware, data files from other machines, etc.

I suggest that this get made a standard extension.

          Paul



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