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Language summary attributes

The concept of attributes is pretty unique to Ada. Attributes allow you to get —and sometimes set— information about objects or other language entities such as types. A good example is the Size attribute. It describes the size of an object or a type in bits.

A : Natural := Integer'Size; -- A is now 32 (with the GNAT compiler for the x86 architecture)

However, unlike the sizeof operator from C/C++ the Size attribute can also be set:

type Byte is range -128 .. 127;  -- The range fits into 8 bits but the
                               -- compiler is still free to choose.
for  Byte'Size use 8;           -- Now we force the compiler to use 8 bits.

Of course not all attributes can be set. An attribute starts with a tick ' and is followed by its name. The compiler determines by context if the tick is the beginning of an attribute, a character literal or a quantified expression.

A : Character := Character'Val (32) -- A is now a space
B : Character := ' ';               -- B is also a space

List of language defined attributes

Ada 2005
This is a new Ada 2005 attribute.
Ada 2012
This is a new Ada 2012 attribute.
Obsolescent
This is a deprecated attribute and should not be used in new code.

A – B

C

D – F

G – L

M

O – R

S

  • 'Safe_Emax (Obsolescent)
  • 'Safe_First
  • 'Safe_Large (Obsolescent)
  • 'Safe_Last
  • 'Safe_Small (Obsolescent)
  • 'Scale
  • 'Scaling
  • 'Signed_Zeros
  • 'Size
  • 'Small
  • 'Storage_Pool
  • 'Storage_Size
  • 'Stream_Size (Ada 2005)
  • 'Succ

T – V

W – Z

  • 'Wide_Image
  • 'Wide_Value
  • 'Wide_Wide_Image (Ada 2005)
  • 'Wide_Wide_Value (Ada 2005)
  • 'Wide_Wide_Width (Ada 2005)
  • 'Wide_Width
  • 'Width
  • 'Write

List of implementation defined attributes

The following attributes are not available in all Ada compilers, only in those that had implemented them.

Currently, there are only listed the implementation-defined attributes of a few compilers. You can help Wikibooks adding specific attributes of other compilers:

GNAT
Implementation-defined attribute of the GNAT compiler from AdaCore/FSF.
HP Ada
Implementation-defined attribute of the HP Ada compiler (formerly known as "DEC Ada").
ICC
Implementation-defined attribute[1] of the Irvine ICC compiler.
PowerAda
Implementation-defined attribute of OC Systems' PowerAda.
SPARCompiler
Implementation-defined attribute of Sun's SPARCompiler Ada.

A – D

  • 'Abort_Signal (GNAT)
  • 'Address_Size (GNAT)
  • 'Architecture (ICC)
  • 'Asm_Input (GNAT)
  • 'Asm_Output (GNAT)
  • 'AST_Entry (GNAT, HP Ada)
  • 'Bit (GNAT, HP Ada)
  • 'Bit_Position (GNAT)
  • 'CG_Mode (ICC)
  • 'Code_Address (GNAT)
  • 'Compiler_Key (SPARCompiler)
  • 'Compiler_Version (SPARCompiler)
  • 'Declared (ICC)
  • 'Default_Bit_Order (GNAT)
  • 'Dope_Address (SPARCompiler)
  • 'Dope_Size (SPARCompiler)

E – H

  • 'Elaborated (GNAT)
  • 'Elab_Body (GNAT)
  • 'Elab_Spec (GNAT)
  • 'Emax (GNAT)
  • 'Enabled (GNAT)
  • 'Entry_Number (SPARCompiler)
  • 'Enum_Rep (GNAT)
  • 'Enum_Val (GNAT)
  • 'Epsilon (GNAT)
  • 'Exception_Address (ICC)
  • 'Extended_Aft (PowerAda)
  • 'Extended_Base (PowerAda)
  • 'Extended_Digits (PowerAda)
  • 'Extended_Fore (PowerAda)
  • 'Extended_Image (PowerAda)
  • 'Extended_Value (PowerAda)
  • 'Extended_Width (PowerAda)
  • 'Extended_Wide_Image (PowerAda)
  • 'Extended_Wide_Value (PowerAda)
  • 'Extended_Wide_Width (PowerAda)
  • 'Fixed_Value (GNAT)
  • 'Has_Access_Values (GNAT)
  • 'Has_Discriminants (GNAT)
  • 'High_Word (ICC)
  • 'Homogeneous (SPARCompiler)

I – N

  • 'Img (GNAT)
  • 'Integer_Value (GNAT)
  • 'Invalid_Value (GNAT)
  • 'Linear_Address (ICC)
  • 'Low_Word (ICC)
  • 'Machine_Size (GNAT, HP Ada)
  • 'Max_Interrupt_Priority (GNAT)
  • 'Max_Priority (GNAT)
  • 'Maximum_Alignment (GNAT)
  • 'Mechanism_Code (GNAT)
  • 'Null_Parameter (GNAT, HP Ada)

O – T

  • 'Object_Size (GNAT)
  • 'Old (GNAT)
  • 'Passed_By_Reference (GNAT)
  • 'Pool_Address (GNAT)
  • 'Range_Length (GNAT)
  • 'Ref (SPARCompiler)
  • 'Storage_Unit (GNAT)
  • 'Stub_Type (GNAT)
  • 'Target (ICC)
  • 'Target_Name (GNAT)
  • 'Task_ID (SPARCompiler)
  • 'Tick (GNAT)
  • 'To_Address (GNAT)
  • 'Type_Class (GNAT, HP Ada)
  • 'Type_Key (SPARCompiler)

U – Z

  • 'UET_Address (GNAT)
  • 'Unconstrained_Array (GNAT)
  • 'Universal_Literal_String (GNAT)
  • 'Unrestricted_Access (GNAT, ICC)
  • 'VADS_Size (GNAT)
  • 'Value_Size (GNAT)
  • 'Wchar_T_Size (GNAT)
  • 'Word_Size (GNAT)

See also

Wikibook

Ada Reference Manual

Ada 83

Ada 95

Ada 2005

Ada 2012

References

  1. ↑ "4.2 ICC-Defined Attributes", ICC Ada Implementation Reference — ICC Ada Version 8.2.5 for i960MC Targets, document version 2.11.4
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