

                                   Annex M
                                (informative)

                   Implementation-Defined Characteristics


1     The Ada language allows for certain machine dependences in a controlled
manner. Each Ada implementation must document all implementation-defined
characteristics:

2     Whether or not each recommendation given in Implementation Advice is
      followed. See 1.1.2(37).

3     Capacity limitations of the implementation. See 1.1.3(3).

4     Variations from the standard that are impractical to avoid given the
      implementation's execution environment. See 1.1.3(6).

5     Which code_statements cause external interactions. See 1.1.3(10).

6     The coded representation for the text of an Ada program. See 2.1(4).

7     The control functions allowed in comments. See 2.1(14).

8     The representation for an end of line. See 2.2(2).

9     Maximum supported line length and lexical element length. See 2.2(14).

10    Implementation-defined pragmas. See 2.8(14).

11    Effect of pragma Optimize. See 2.8(27).

12    The sequence of characters of the value returned by S'Image when some of
      the graphic characters of S'Wide_Image are not defined in Character. See
      3.5(37).

13    The predefined integer types declared in Standard. See 3.5.4(25).

14    Any nonstandard integer types and the operators defined for them. See
      3.5.4(26).

15    Any nonstandard real types and the operators defined for them. See
      3.5.6(8).

16    What combinations of requested decimal precision and range are supported
      for floating point types. See 3.5.7(7).

17    The predefined floating point types declared in Standard. See 3.5.7(16).

18    The small of an ordinary fixed point type. See 3.5.9(8).

19    What combinations of small, range, and digits are supported for fixed
      point types. See 3.5.9(10).

20    The result of Tags.Expanded_Name for types declared within an unnamed
      block_statement. See 3.9(10).

21    Implementation-defined attributes. See 4.1.4(12/1).

22    Any implementation-defined time types. See 9.6(6).

23    The time base associated with relative delays. See 9.6(20).

24    The time base of the type Calendar.Time. See 9.6(23).

25    The timezone used for package Calendar operations. See 9.6(24).

26    Any limit on delay_until_statements of select_statements. See 9.6(29).

27    Whether or not two nonoverlapping parts of a composite object are
      independently addressable, in the case where packing, record layout, or
      Component_Size is specified for the object. See 9.10(1).

28    The representation for a compilation. See 10.1(2).

29    Any restrictions on compilations that contain multiple
      compilation_units. See 10.1(4).

30    The mechanisms for creating an environment and for adding and replacing
      compilation units. See 10.1.4(3).

31    The implementation-defined means, if any, of specifying which
      compilation units are needed by a given compilation unit. See 10.2(2).

32    The manner of explicitly assigning library units to a partition. See
      10.2(2).

33    The manner of designating the main subprogram of a partition. See
      10.2(7).

34    The order of elaboration of library_items. See 10.2(18).

35    Parameter passing and function return for the main subprogram. See
      10.2(21).

36    The mechanisms for building and running partitions. See 10.2(24).

37    The details of program execution, including program termination. See
      10.2(25).

38    The semantics of any nonactive partitions supported by the
      implementation. See 10.2(28).

39    The information returned by Exception_Message. See 11.4.1(10).

40    The result of Exceptions.Exception_Name for types declared within an
      unnamed block_statement. See 11.4.1(12).

41    The information returned by Exception_Information. See 11.4.1(13).

42    Implementation-defined check names. See 11.5(27).

43    Any restrictions placed upon representation items. See 13.1(20).

44    The interpretation of each aspect of representation. See 13.1(20).

45    The meaning of Size for indefinite subtypes. See 13.3(48).

46    The default external representation for a type tag. See 13.3(75/1).

47    What determines whether a compilation unit is the same in two different
      partitions. See 13.3(76).

48    Implementation-defined components. See 13.5.1(15).

49    If Word_Size = Storage_Unit, the default bit ordering. See 13.5.3(5).

50    The contents of the visible part of package System and its
      language-defined children. See 13.7(2).

51    The contents of the visible part of package System.Machine_Code, and the
      meaning of code_statements. See 13.8(7).

52    The effect of unchecked conversion. See 13.9(11).

53    Whether or not the implementation provides user-accessible names for the
      standard pool type(s). See 13.11(17).

54    The manner of choosing a storage pool for an access type when
      Storage_Pool is not specified for the type. See 13.11(17).

55    The meaning of Storage_Size. See 13.11(18).

56    Implementation-defined aspects of storage pools. See 13.11(22).

57    The set of restrictions allowed in a pragma Restrictions. See 13.12(7).

58    The consequences of violating limitations on Restrictions pragmas. See
      13.12(9).

59    The representation used by the Read and Write attributes of elementary
      types in terms of stream elements. See 13.13.2(9).

60    The names and characteristics of the numeric subtypes declared in the
      visible part of package Standard. See A.1(3).

61    The accuracy actually achieved by the elementary functions. See A.5.1(1).

62    The sign of a zero result from some of the operators or functions in
      Numerics.Generic_Elementary_Functions, when Float_Type'Signed_Zeros is
      True. See A.5.1(46).

63    The value of Numerics.Discrete_Random.Max_Image_Width. See A.5.2(27).

64    The value of Numerics.Float_Random.Max_Image_Width. See A.5.2(27).

65    The algorithms for random number generation. See A.5.2(32).

66    The string representation of a random number generator's state. See
      A.5.2(38).

67    The minimum time interval between calls to the time-dependent Reset
      procedure that are guaranteed to initiate different random number
      sequences. See A.5.2(45).

68    The values of the Model_Mantissa, Model_Emin, Model_Epsilon, Model,
      Safe_First, and Safe_Last attributes, if the Numerics Annex is not
      supported. See A.5.3(72).

69    Any implementation-defined characteristics of the input-output packages.
      See A.7(14).

70    The value of Buffer_Size in Storage_IO. See A.9(10).

71    external files for standard input, standard output, and standard error
      See A.10(5).

72    The accuracy of the value produced by Put. See A.10.9(36).

72.1/1 Current size for a stream file for which positioning is not supported.
      See A.12.1(1.1/1).

73    The meaning of Argument_Count, Argument, and Command_Name. See A.15(1).

74    Implementation-defined convention names. See B.1(11).

75    The manner of choosing link names when neither the link name nor the
      address of an imported or exported entity is specified. See B.1(36).

76    The meaning of link names. See B.1(36).

77    The effect of pragma Linker_Options. See B.1(37).

78    The contents of the visible part of package Interfaces and its
      language-defined descendants. See B.2(1).

79    Implementation-defined children of package Interfaces. The contents of
      the visible part of package Interfaces. See B.2(11).

79.1/1 The definitions of types and constants in Interfaces.C. See B.3(41).

80/1  The types Floating, Long_Floating, Binary, Long_Binary, Decimal_Element,
      and COBOL_Character; and the initializations of the variables
      Ada_To_COBOL and COBOL_To_Ada, in Interfaces.COBOL. See B.4(50).

80.1/1 The types Fortran_Integer, Real, Double_Precision, and Character_Set in
      Interfaces.Fortran. See B.5(17).

81    Support for access to machine instructions. See C.1(1).

82    Implementation-defined aspects of access to machine operations. See
      C.1(9).

83    Implementation-defined aspects of interrupts. See C.3(2).

84    Implementation-defined aspects of preelaboration. See C.4(13).

85    The semantics of pragma Discard_Names. See C.5(7).

86    The result of the Task_Identification.Image attribute. See C.7.1(7).

87    The value of Current_Task when in a protected entry or interrupt
      handler. See C.7.1(17).

88    The effect of calling Current_Task from an entry body or interrupt
      handler. See C.7.1(19).

88.1/1 Granularity of locking for Task_Attributes. See C.7.2(16/1).

89/1  Limits on the number and size of task attributes, and how to configure
      them. See C.7.2(19).

90    Values of all Metrics. See D(2).

91    The declarations of Any_Priority and Priority. See D.1(11).

92    Implementation-defined execution resources. See D.1(15).

93    Whether, on a multiprocessor, a task that is waiting for access to a
      protected object keeps its processor busy. See D.2.1(3).

94    The affect of implementation defined execution resources on task
      dispatching. See D.2.1(9).

95    Implementation-defined policy_identifiers allowed in a pragma
      Task_Dispatching_Policy. See D.2.2(3).

96    Implementation-defined aspects of priority inversion. See D.2.2(16).

97    Implementation defined task dispatching. See D.2.2(18).

98    Implementation-defined policy_identifiers allowed in a pragma
      Locking_Policy. See D.3(4).

99    Default ceiling priorities. See D.3(10).

100   The ceiling of any protected object used internally by the
      implementation. See D.3(16).

101   Implementation-defined queuing policies. See D.4(1/1).

102   On a multiprocessor, any conditions that cause the completion of an
      aborted construct to be delayed later than what is specified for a
      single processor. See D.6(3).

103   Any operations that implicitly require heap storage allocation. See
      D.7(8).

104   Implementation-defined aspects of pragma Restrictions. See D.7(20).

105   Implementation-defined aspects of package Real_Time. See D.8(17).

106   Implementation-defined aspects of delay_statements. See D.9(8).

107   The upper bound on the duration of interrupt blocking caused by the
      implementation. See D.12(5).

108   The means for creating and executing distributed programs. See E(5).

109   Any events that can result in a partition becoming inaccessible. See
      E.1(7).

110   The scheduling policies, treatment of priorities, and management of
      shared resources between partitions in certain cases. See E.1(11).

111/1 This paragraph was deleted.

112   Whether the execution of the remote subprogram is immediately aborted as
      a result of cancellation. See E.4(13).

113   Implementation-defined aspects of the PCS. See E.5(25).

114   Implementation-defined interfaces in the PCS. See E.5(26).

115   The values of named numbers in the package Decimal. See F.2(7).

116   The value of Max_Picture_Length in the package Text_IO.Editing See
      F.3.3(16).

117   The value of Max_Picture_Length in the package Wide_Text_IO.Editing See
      F.3.4(5).

118   The accuracy actually achieved by the complex elementary functions and
      by other complex arithmetic operations. See G.1(1).

119   The sign of a zero result (or a component thereof) from any operator or
      function in Numerics.Generic_Complex_Types, when Real'Signed_Zeros is
      True. See G.1.1(53).

120   The sign of a zero result (or a component thereof) from any operator or
      function in Numerics.Generic_Complex_Elementary_Functions, when
      Complex_Types.Real'Signed_Zeros is True. See G.1.2(45).

121   Whether the strict mode or the relaxed mode is the default. See G.2(2).

122   The result interval in certain cases of fixed-to-float conversion. See
      G.2.1(10).

123   The result of a floating point arithmetic operation in overflow
      situations, when the Machine_Overflows attribute of the result type is
      False. See G.2.1(13).

124   The result interval for division (or exponentiation by a negative
      exponent), when the floating point hardware implements division as
      multiplication by a reciprocal. See G.2.1(16).

125   The definition of close result set, which determines the accuracy of
      certain fixed point multiplications and divisions. See G.2.3(5).

126   Conditions on a universal_real operand of a fixed point multiplication
      or division for which the result shall be in the perfect result set. See
      G.2.3(22).

127   The result of a fixed point arithmetic operation in overflow situations,
      when the Machine_Overflows attribute of the result type is False. See
      G.2.3(27).

128   The result of an elementary function reference in overflow situations,
      when the Machine_Overflows attribute of the result type is False. See
      G.2.4(4).

129   The accuracy of certain elementary functions for parameters beyond the
      angle threshold. See G.2.4(10).

130   The value of the angle threshold, within which certain elementary
      functions, complex arithmetic operations, and complex elementary
      functions yield results conforming to a maximum relative error bound.
      See G.2.4(10).

131   The result of a complex arithmetic operation or complex elementary
      function reference in overflow situations, when the Machine_Overflows
      attribute of the corresponding real type is False. See G.2.6(5).

132   The accuracy of certain complex arithmetic operations and certain
      complex elementary functions for parameters (or components thereof)
      beyond the angle threshold. See G.2.6(8).

133   Information regarding bounded errors and erroneous execution. See H.2(1).

134   Implementation-defined aspects of pragma Inspection_Point. See H.3.2(8).

135   Implementation-defined aspects of pragma Restrictions. See H.4(25).

136   Any restrictions on pragma Restrictions. See H.4(27).

