Requirement to Implement pragmas?

[harbaughs@eglin-vax]

I observe validated compilers not implementing all predefined pragmas
and then I read in LRM section 2.8 (8) "The pragmas defined by the
language are desribed in Annex B: they must be supported by every
implementation."     
   As an example, but not to talk negatively about the product, I cite
from the Alsys PC/AT compiler appendix F:
"pragma shared is currently ignored."
"Some other predefined pragmas are not treated at this time. If used they
are ignored and a warning is issued. These pragmas are CONTROLLED, INLINE,
MEMORY_SIZE, OPTIMIZE, PACK, STORAGE_UNIT, SYSTEM_NAME."
Above quotes are from version 1.0 20 Feb 1986 which I believe is validated.
            
    As a second example, again not to talk negatively about the product, I
cite the VAX Ada LRM:
"VAX Ada does not support pragma SHARED(see VOLATILE)"
"VAX Ada does not support pragma SUPPRESS(see SUPPRESS_ALL)"
--
   It seems that vendors are allowed latitude with pragmas beyond my
interpretation of section 2.8 (8). I don't say that is necessarily
bad, I am just asking for an explanation. Thanks.
regards, sam harbaugh
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