GNAT Reference Manual

GNAT, The GNU Ada Compiler
GNAT GPL Edition, Version 2012
Document revision level 247883
Date: 2012/04/30

AdaCore

Copyright (C) 1995-2011, Free Software Foundation

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being "GNU Free Documentation License", with the Front-Cover Texts being "GNAT Reference Manual", and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

About This Guide
1. Implementation Defined Pragmas
2. Implementation Defined Attributes
3. Standard and Implementation Defined Restrictions
4. Implementation Advice
5. Implementation Defined Characteristics
6. Intrinsic Subprograms
7. Representation Clauses and Pragmas
8. Standard Library Routines
9. The Implementation of Standard I/O
10. The GNAT Library
11. Interfacing to Other Languages
12. Specialized Needs Annexes
13. Implementation of Specific Ada Features
14. Implementation of Ada 2012 Features
15. Obsolescent Features
A. GNU Free Documentation License
Index

 -- The Detailed Node Listing --- About This Guide

What This Reference Manual Contains
Related Information

Implementation Defined Pragmas

Pragma Abort_Defer
Pragma Ada_83
Pragma Ada_95
Pragma Ada_05
Pragma Ada_2005
Pragma Ada_12
Pragma Ada_2012
Pragma Annotate
Pragma Assert
Pragma Assertion_Policy
Pragma Assume_No_Invalid_Values
Pragma Ast_Entry
Pragma C_Pass_By_Copy
Pragma Check
Pragma Check_Name
Pragma Check_Policy
Pragma Comment
Pragma Common_Object
Pragma Compile_Time_Error
Pragma Compile_Time_Warning
Pragma Compiler_Unit
Pragma Complete_Representation
Pragma Complex_Representation
Pragma Component_Alignment
Pragma Contract_Case
Pragma Convention_Identifier
Pragma CPP_Class
Pragma CPP_Constructor
Pragma CPP_Virtual
Pragma CPP_Vtable
Pragma Debug
Pragma Debug_Policy
Pragma Detect_Blocking
Pragma Elaboration_Checks
Pragma Eliminate
Pragma Export_Exception
Pragma Export_Function
Pragma Export_Object
Pragma Export_Procedure
Pragma Export_Value
Pragma Export_Valued_Procedure
Pragma Extend_System
Pragma Extensions_Allowed
Pragma External
Pragma External_Name_Casing
Pragma Fast_Math
Pragma Favor_Top_Level
Pragma Finalize_Storage_Only
Pragma Float_Representation
Pragma Ident
Pragma Implemented
Pragma Implicit_Packing
Pragma Import_Exception
Pragma Import_Function
Pragma Import_Object
Pragma Import_Procedure
Pragma Import_Valued_Procedure
Pragma Initialize_Scalars
Pragma Inline_Always
Pragma Inline_Generic
Pragma Interface
Pragma Interface_Name
Pragma Interrupt_Handler
Pragma Interrupt_State
Pragma Invariant
Pragma Keep_Names
Pragma License
Pragma Link_With
Pragma Linker_Alias
Pragma Linker_Constructor
Pragma Linker_Destructor
Pragma Linker_Section
Pragma Long_Float
Pragma Machine_Attribute
Pragma Main
Pragma Main_Storage
Pragma No_Body
Pragma No_Return
Pragma No_Strict_Aliasing
Pragma Normalize_Scalars
Pragma Obsolescent
Pragma Optimize_Alignment
Pragma Ordered
Pragma Passive
Pragma Persistent_BSS
Pragma Polling
Pragma Postcondition
Pragma Precondition
Pragma Profile (Ravenscar)
Pragma Profile (Restricted)
Pragma Psect_Object
Pragma Pure_Function
Pragma Remote_Access_Type
Pragma Restriction_Warnings
Pragma Shared
Pragma Short_Circuit_And_Or
Pragma Short_Descriptors
Pragma Simple_Storage_Pool_Type
Pragma Source_File_Name
Pragma Source_File_Name_Project
Pragma Source_Reference
Pragma Static_Elaboration_Desired
Pragma Stream_Convert
Pragma Style_Checks
Pragma Subtitle
Pragma Suppress
Pragma Suppress_All
Pragma Suppress_Exception_Locations
Pragma Suppress_Initialization
Pragma Task_Info
Pragma Task_Name
Pragma Task_Storage
Pragma Test_Case
Pragma Thread_Local_Storage
Pragma Time_Slice
Pragma Title
Pragma Unchecked_Union
Pragma Unimplemented_Unit
Pragma Universal_Aliasing
Pragma Universal_Data
Pragma Unmodified
Pragma Unreferenced
Pragma Unreferenced_Objects
Pragma Unreserve_All_Interrupts
Pragma Unsuppress
Pragma Use_VADS_Size
Pragma Validity_Checks
Pragma Volatile
Pragma Warnings
Pragma Weak_External
Pragma Wide_Character_Encoding

Implementation Defined Attributes

Abort_Signal
Address_Size
Asm_Input
Asm_Output
AST_Entry
Bit
Bit_Position
Compiler_Version
Code_Address
Default_Bit_Order
Descriptor_Size
Elaborated
Elab_Body
Elab_Spec
Elab_Subp_Body
Emax
Enabled
Enum_Rep
Enum_Val
Epsilon
Fixed_Value
Has_Access_Values
Has_Discriminants
Img
Integer_Value
Invalid_Value
Large
Machine_Size
Mantissa
Max_Interrupt_Priority
Max_Priority
Maximum_Alignment
Mechanism_Code
Null_Parameter
Object_Size
Old
Passed_By_Reference
Pool_Address
Range_Length
Result
Safe_Emax
Safe_Large
Scalar_Storage_Order
Simple_Storage_Pool
Small
Storage_Unit
Stub_Type
System_Allocator_Alignment
Target_Name
Tick
To_Address
Type_Class
UET_Address
Unconstrained_Array
Universal_Literal_String
Unrestricted_Access
Valid_Scalars
VADS_Size
Value_Size
Wchar_T_Size
Word_Size

Standard and Implementation Defined Restrictions

3.1 Partition-Wide Restrictions
3.2 Program Unit Level Restrictions

Partition-Wide Restrictions

Immediate_Reclamation
Max_Asynchronous_Select_Nesting
Max_Entry_Queue_Length
Max_Protected_Entries
Max_Select_Alternatives
Max_Storage_At_Blocking
Max_Task_Entries
Max_Tasks
No_Abort_Statements
No_Access_Parameter_Allocators
No_Access_Subprograms
No_Allocators
No_Anonymous_Allocators
No_Calendar
No_Coextensions
No_Default_Initialization
No_Delay
No_Dependence
No_Direct_Boolean_Operators
No_Dispatch
No_Dispatching_Calls
No_Dynamic_Attachment
No_Dynamic_Priorities
No_Entry_Calls_In_Elaboration_Code
No_Enumeration_Maps
No_Exception_Handlers
No_Exception_Propagation
No_Exception_Registration
No_Exceptions
No_Finalization
No_Fixed_Point
No_Floating_Point
No_Implicit_Conditionals
No_Implicit_Dynamic_Code
No_Implicit_Heap_Allocations
No_Implicit_Loops
No_Initialize_Scalars
No_IO
No_Local_Allocators
No_Local_Protected_Objects
No_Local_Timing_Events
No_Nested_Finalization
No_Protected_Type_Allocators
No_Protected_Types
No_Recursion
No_Reentrancy
No_Relative_Delay
No_Requeue_Statements
No_Secondary_Stack
No_Select_Statements
No_Specific_Termination_Handlers
No_Specification_of_Aspect
No_Standard_Allocators_After_Elaboration
No_Standard_Storage_Pools
No_Stream_Optimizations
No_Streams
No_Task_Allocators
No_Task_Attributes_Package
No_Task_Hierarchy
No_Task_Termination
No_Tasking
No_Terminate_Alternatives
No_Unchecked_Access
Simple_Barriers
Static_Priorities
Static_Storage_Size

Program Unit Level Restrictions

No_Elaboration_Code
No_Entry_Queue
No_Implementation_Aspect_Specifications
No_Implementation_Attributes
No_Implementation_Identifiers
No_Implementation_Pragmas
No_Implementation_Restrictions
No_Implementation_Units
No_Implicit_Aliasing
No_Obsolescent_Features
No_Wide_Characters
SPARK

The Implementation of Standard I/O

9.1 Standard I/O Packages
9.2 FORM Strings
9.3 Direct_IO
9.4 Sequential_IO
9.5 Text_IO
9.6 Wide_Text_IO
9.7 Wide_Wide_Text_IO
9.8 Stream_IO
9.9 Text Translation
9.10 Shared Files
9.11 Filenames encoding
9.12 Open Modes
9.13 Operations on C Streams
9.14 Interfacing to C Streams

The GNAT Library

10.1 Ada.Characters.Latin_9 (`a-chlat9.ads')
10.2 Ada.Characters.Wide_Latin_1 (`a-cwila1.ads')
10.3 Ada.Characters.Wide_Latin_9 (`a-cwila1.ads')
10.4 Ada.Characters.Wide_Wide_Latin_1 (`a-chzla1.ads')
10.5 Ada.Characters.Wide_Wide_Latin_9 (`a-chzla9.ads')
10.6 Ada.Containers.Formal_Doubly_Linked_Lists (`a-cfdlli.ads')
10.7 Ada.Containers.Formal_Hashed_Maps (`a-cfhama.ads')
10.8 Ada.Containers.Formal_Hashed_Sets (`a-cfhase.ads')
10.9 Ada.Containers.Formal_Ordered_Maps (`a-cforma.ads')
10.10 Ada.Containers.Formal_Ordered_Sets (`a-cforse.ads')
10.11 Ada.Containers.Formal_Vectors (`a-cofove.ads')
10.12 Ada.Command_Line.Environment (`a-colien.ads')
10.13 Ada.Command_Line.Remove (`a-colire.ads')
10.14 Ada.Command_Line.Response_File (`a-clrefi.ads')
10.15 Ada.Direct_IO.C_Streams (`a-diocst.ads')
10.16 Ada.Exceptions.Is_Null_Occurrence (`a-einuoc.ads')
10.17 Ada.Exceptions.Last_Chance_Handler (`a-elchha.ads')
10.18 Ada.Exceptions.Traceback (`a-exctra.ads')
10.19 Ada.Sequential_IO.C_Streams (`a-siocst.ads')
10.20 Ada.Streams.Stream_IO.C_Streams (`a-ssicst.ads')
10.21 Ada.Strings.Unbounded.Text_IO (`a-suteio.ads')
10.22 Ada.Strings.Wide_Unbounded.Wide_Text_IO (`a-swuwti.ads')
10.23 Ada.Strings.Wide_Wide_Unbounded.Wide_Wide_Text_IO (`a-szuzti.ads')
10.24 Ada.Text_IO.C_Streams (`a-tiocst.ads')
10.25 Ada.Text_IO.Reset_Standard_Files (`a-tirsfi.ads')
10.26 Ada.Wide_Characters.Unicode (`a-wichun.ads')
10.27 Ada.Wide_Text_IO.C_Streams (`a-wtcstr.ads')
10.28 Ada.Wide_Text_IO.Reset_Standard_Files (`a-wrstfi.ads')
10.29 Ada.Wide_Wide_Characters.Unicode (`a-zchuni.ads')
10.30 Ada.Wide_Wide_Text_IO.C_Streams (`a-ztcstr.ads')
10.31 Ada.Wide_Wide_Text_IO.Reset_Standard_Files (`a-zrstfi.ads')
10.32 GNAT.Altivec (`g-altive.ads')
10.33 GNAT.Altivec.Conversions (`g-altcon.ads')
10.34 GNAT.Altivec.Vector_Operations (`g-alveop.ads')
10.35 GNAT.Altivec.Vector_Types (`g-alvety.ads')
10.36 GNAT.Altivec.Vector_Views (`g-alvevi.ads')
10.37 GNAT.Array_Split (`g-arrspl.ads')
10.38 GNAT.AWK (`g-awk.ads')
10.39 GNAT.Bounded_Buffers (`g-boubuf.ads')
10.40 GNAT.Bounded_Mailboxes (`g-boumai.ads')
10.41 GNAT.Bubble_Sort (`g-bubsor.ads')
10.42 GNAT.Bubble_Sort_A (`g-busora.ads')
10.43 GNAT.Bubble_Sort_G (`g-busorg.ads')
10.44 GNAT.Byte_Order_Mark (`g-byorma.ads')
10.45 GNAT.Byte_Swapping (`g-bytswa.ads')
10.46 GNAT.Calendar (`g-calend.ads')
10.47 GNAT.Calendar.Time_IO (`g-catiio.ads')
10.49 GNAT.Case_Util (`g-casuti.ads')
10.50 GNAT.CGI (`g-cgi.ads')
10.51 GNAT.CGI.Cookie (`g-cgicoo.ads')
10.52 GNAT.CGI.Debug (`g-cgideb.ads')
10.53 GNAT.Command_Line (`g-comlin.ads')
10.54 GNAT.Compiler_Version (`g-comver.ads')
10.55 GNAT.Ctrl_C (`g-ctrl_c.ads')
10.48 GNAT.CRC32 (`g-crc32.ads')
10.56 GNAT.Current_Exception (`g-curexc.ads')
10.57 GNAT.Debug_Pools (`g-debpoo.ads')
10.58 GNAT.Debug_Utilities (`g-debuti.ads')
10.59 GNAT.Decode_String (`g-decstr.ads')
10.60 GNAT.Decode_UTF8_String (`g-deutst.ads')
10.61 GNAT.Directory_Operations (`g-dirope.ads')
10.62 GNAT.Directory_Operations.Iteration (`g-diopit.ads')
10.63 GNAT.Dynamic_HTables (`g-dynhta.ads')
10.64 GNAT.Dynamic_Tables (`g-dyntab.ads')
10.65 GNAT.Encode_String (`g-encstr.ads')
10.66 GNAT.Encode_UTF8_String (`g-enutst.ads')
10.67 GNAT.Exception_Actions (`g-excact.ads')
10.68 GNAT.Exception_Traces (`g-exctra.ads')
10.69 GNAT.Exceptions (`g-expect.ads')
10.70 GNAT.Expect (`g-expect.ads')
10.71 GNAT.Expect.TTY (`g-exptty.ads')
10.72 GNAT.Float_Control (`g-flocon.ads')
10.73 GNAT.Heap_Sort (`g-heasor.ads')
10.74 GNAT.Heap_Sort_A (`g-hesora.ads')
10.75 GNAT.Heap_Sort_G (`g-hesorg.ads')
10.76 GNAT.HTable (`g-htable.ads')
10.77 GNAT.IO (`g-io.ads')
10.78 GNAT.IO_Aux (`g-io_aux.ads')
10.79 GNAT.Lock_Files (`g-locfil.ads')
10.80 GNAT.MBBS_Discrete_Random (`g-mbdira.ads')
10.81 GNAT.MBBS_Float_Random (`g-mbflra.ads')
10.82 GNAT.MD5 (`g-md5.ads')
10.83 GNAT.Memory_Dump (`g-memdum.ads')
10.84 GNAT.Most_Recent_Exception (`g-moreex.ads')
10.85 GNAT.OS_Lib (`g-os_lib.ads')
10.86 GNAT.Perfect_Hash_Generators (`g-pehage.ads')
10.87 GNAT.Random_Numbers (`g-rannum.ads')
10.88 GNAT.Regexp (`g-regexp.ads')
10.89 GNAT.Registry (`g-regist.ads')
10.90 GNAT.Regpat (`g-regpat.ads')
10.91 GNAT.Secondary_Stack_Info (`g-sestin.ads')
10.92 GNAT.Semaphores (`g-semaph.ads')
10.93 GNAT.Serial_Communications (`g-sercom.ads')
10.94 GNAT.SHA1 (`g-sha1.ads')
10.95 GNAT.SHA224 (`g-sha224.ads')
10.96 GNAT.SHA256 (`g-sha256.ads')
10.97 GNAT.SHA384 (`g-sha384.ads')
10.98 GNAT.SHA512 (`g-sha512.ads')
10.99 GNAT.Signals (`g-signal.ads')
10.100 GNAT.Sockets (`g-socket.ads')
10.101 GNAT.Source_Info (`g-souinf.ads')
10.102 GNAT.Spelling_Checker (`g-speche.ads')
10.103 GNAT.Spelling_Checker_Generic (`g-spchge.ads')
10.104 GNAT.Spitbol.Patterns (`g-spipat.ads')
10.105 GNAT.Spitbol (`g-spitbo.ads')
10.106 GNAT.Spitbol.Table_Boolean (`g-sptabo.ads')
10.107 GNAT.Spitbol.Table_Integer (`g-sptain.ads')
10.108 GNAT.Spitbol.Table_VString (`g-sptavs.ads')
10.109 GNAT.SSE (`g-sse.ads')
10.110 GNAT.SSE.Vector_Types (`g-ssvety.ads')
10.111 GNAT.Strings (`g-string.ads')
10.112 GNAT.String_Split (`g-strspl.ads')
10.113 GNAT.Table (`g-table.ads')
10.114 GNAT.Task_Lock (`g-tasloc.ads')
10.116 GNAT.Threads (`g-thread.ads')
10.115 GNAT.Time_Stamp (`g-timsta.ads')
10.117 GNAT.Traceback (`g-traceb.ads')
10.118 GNAT.Traceback.Symbolic (`g-trasym.ads')
10.119 GNAT.UTF_32 (`g-table.ads')
10.120 GNAT.Wide_Spelling_Checker (`g-u3spch.ads')
10.121 GNAT.Wide_Spelling_Checker (`g-wispch.ads')
10.122 GNAT.Wide_String_Split (`g-wistsp.ads')
10.123 GNAT.Wide_Wide_Spelling_Checker (`g-zspche.ads')
10.124 GNAT.Wide_Wide_String_Split (`g-zistsp.ads')
10.125 Interfaces.C.Extensions (`i-cexten.ads')
10.126 Interfaces.C.Streams (`i-cstrea.ads')
10.127 Interfaces.CPP (`i-cpp.ads')
10.128 Interfaces.Packed_Decimal (`i-pacdec.ads')
10.129 Interfaces.VxWorks (`i-vxwork.ads')
10.130 Interfaces.VxWorks.IO (`i-vxwoio.ads')
10.131 System.Address_Image (`s-addima.ads')
10.132 System.Assertions (`s-assert.ads')
10.133 System.Memory (`s-memory.ads')
10.134 System.Partition_Interface (`s-parint.ads')
10.135 System.Pool_Global (`s-pooglo.ads')
10.136 System.Pool_Local (`s-pooloc.ads')
10.137 System.Restrictions (`s-restri.ads')
10.138 System.Rident (`s-rident.ads')
10.139 System.Strings.Stream_Ops (`s-ststop.ads')
10.140 System.Task_Info (`s-tasinf.ads')
10.141 System.Wch_Cnv (`s-wchcnv.ads')
10.142 System.Wch_Con (`s-wchcon.ads')

Text_IO

9.5.1 Stream Pointer Positioning
9.5.2 Reading and Writing Non-Regular Files
9.5.3 Get_Immediate
9.5.4 Treating Text_IO Files as Streams
9.5.5 Text_IO Extensions
9.5.6 Text_IO Facilities for Unbounded Strings

Wide_Text_IO

9.6.1 Stream Pointer Positioning
9.6.2 Reading and Writing Non-Regular Files

Wide_Wide_Text_IO

9.7.1 Stream Pointer Positioning
9.7.2 Reading and Writing Non-Regular Files

Interfacing to Other Languages

11.1 Interfacing to C
11.2 Interfacing to C++
11.3 Interfacing to COBOL
11.4 Interfacing to Fortran
11.5 Interfacing to non-GNAT Ada code

Specialized Needs Annexes Implementation of Specific Ada Features

13.1 Machine Code Insertions
13.2 GNAT Implementation of Tasking
13.3 GNAT Implementation of Shared Passive Packages
13.4 Code Generation for Array Aggregates
13.5 The Size of Discriminated Records with Default Discriminants
13.6 Strict Conformance to the Ada Reference Manual

Implementation of Ada 2012 Features Obsolescent Features GNU Free Documentation License Index