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1.1.3 Conformity of an Implementation with the Standard
conforming implementation shall:
- Translate and correctly execute legal
programs written in Ada, provided that they are not so large as to exceed
the capacity of the implementation;
- Identify all programs or program units
that are so large as to exceed the capacity of the implementation (or
raise an appropriate exception at run time);
- Identify all programs or program units
that contain errors whose detection is required by this International
- Supply all language-defined library
units required by this International Standard;
- Contain no variations except those
explicitly permitted by this International Standard, or those that are
impossible or impractical to avoid given the implementation's execution
- Specify all such variations in the
manner prescribed by this International Standard.
of the execution of an Ada program is defined
in terms of its interactions with its external environment.
following are defined as external interactions
- Any interaction with an external file
- The execution of certain code_statements
(see 13.8); which code_statements
cause external interactions is implementation defined.
- Any call on an imported subprogram
(see Annex B), including any parameters passed
- Any result returned or exception propagated
from a main subprogram (see 10.2) or an exported
subprogram (see Annex B) to an external caller;
- Any read or update of an atomic or
volatile object (see C.6);
- The values of imported and exported
objects (see Annex B) at the time of any other
interaction with the external environment.
A conforming implementation of this International
Standard shall produce for the execution of a given Ada program a set
of interactions with the external environment whose order and timing
are consistent with the definitions and requirements of this International
Standard for the semantics of the given program.
An implementation that conforms to this Standard
shall support each capability required by the core language as specified.
In addition, an implementation that conforms to this Standard may conform
to one or more Specialized Needs Annexes (or to none). Conformance to
a Specialized Needs Annex means that each capability required by the
Annex is provided as specified.
An implementation conforming to this International
Standard may provide additional attributes, library units, and pragmas.
However, it shall not provide any attribute, library unit, or pragma
having the same name as an attribute, library unit, or pragma (respectively)
specified in a Specialized Needs Annex unless the provided construct
is either as specified in the Specialized Needs Annex or is more limited
in capability than that required by the Annex. A program that attempts
to use an unsupported capability of an Annex shall either be identified
by the implementation before run time or shall raise an exception at
aspects of the semantics are defined to be either implementation defined
. In such cases, the set of possible effects is
specified, and the implementation may choose any effect in the set. Implementations
shall document their behavior in implementation-defined situations, but
documentation is not required for unspecified situations. The implementation-defined
characteristics are summarized in Annex M
The implementation may choose to document implementation-defined
behavior either by documenting what happens in general, or by providing
some mechanism for the user to determine what happens in a particular
If an implementation detects
the use of an unsupported Specialized Needs Annex feature at run time,
it should raise Program_Error if feasible.
If an implementation wishes to provide implementation-defined
extensions to the functionality of a language-defined library unit, it
should normally do so by adding children to the library unit.
2 The above requirements
imply that an implementation conforming to this Standard may support
some of the capabilities required by a Specialized Needs Annex without
supporting all required capabilities.
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