Help with blockread/blockwrite

[Frank Heckenbach]

Peter Norton wrote:

> Chuck F wrote:
> > An integer requires 4 bytes, and must be aligned at
> a multiple of 4.
> 
> Fairly say I never heard about it must be aligned in
> record.

Strictly speaking it doesn't *have* to be aligned. On some
processors (including Intel x86) unaligned access causes some
performance penalty.

Other processors (e.g., Sparc) don't support unaligned access, so
the complier has to work around it using partial accesses, shifts,
etc. This obviously causes a big performance hit (even more when
writing).

So the default is to align properly. This is BTW not specific to
Pascal (the Pascal standards don't say anything about alignment),
but holds for any language that supports such types at all.

Frank

-- 
Frank Heckenbach, frank at g-n-u.de, http://fjf.gnu.de/, 7977168E
GPC To-Do list, latest features, fixed bugs:
http://www.gnu-pascal.de/todo.html
GPC download signing key: 51FF C1F0 1A77 C6C2 4482  4DDC 117A 9773 7F88 1707