9. The GNAT Library

The GNAT library contains a number of general and special purpose packages. It represents functionality that the GNAT developers have found useful, and which is made available to GNAT users. The packages described here are fully supported, and upwards compatibility will be maintained in future releases, so you can use these facilities with the confidence that the same functionality will be available in future releases.

The chapter here simply gives a brief summary of the facilities available. The full documentation is found in the spec file for the package. The full sources of these library packages, including both spec and body, are provided with all GNAT releases. For example, to find out the full specifications of the SPITBOL pattern matching capability, including a full tutorial and extensive examples, look in the `g-spipat.ads' file in the library.

For each entry here, the package name (as it would appear in a with clause) is given, followed by the name of the corresponding spec file in parentheses. The packages are children in four hierarchies, Ada, Interfaces, System, and GNAT, the latter being a GNAT-specific hierarchy.

Note that an application program should only use packages in one of these four hierarchies if the package is defined in the Ada Reference Manual, or is listed in this section of the GNAT Programmers Reference Manual. All other units should be considered internal implementation units and should not be directly with'ed by application code. The use of a with statement that references one of these internal implementation units makes an application potentially dependent on changes in versions of GNAT, and will generate a warning message.

9.1 Ada.Characters.Latin_9 (`a-chlat9.ads')
9.2 Ada.Characters.Wide_Latin_1 (`a-cwila1.ads')
9.3 Ada.Characters.Wide_Latin_9 (`a-cwila1.ads')
9.4 Ada.Characters.Wide_Wide_Latin_1 (`a-chzla1.ads')
9.5 Ada.Characters.Wide_Wide_Latin_9 (`a-chzla9.ads')
9.6 Ada.Command_Line.Environment (`a-colien.ads')
9.7 Ada.Command_Line.Remove (`a-colire.ads')
9.8 Ada.Command_Line.Response_File (`a-clrefi.ads')
9.9 Ada.Direct_IO.C_Streams (`a-diocst.ads')
9.10 Ada.Exceptions.Is_Null_Occurrence (`a-einuoc.ads')
9.11 Ada.Exceptions.Last_Chance_Handler (`a-elchha.ads')
9.12 Ada.Exceptions.Traceback (`a-exctra.ads')
9.13 Ada.Sequential_IO.C_Streams (`a-siocst.ads')
9.14 Ada.Streams.Stream_IO.C_Streams (`a-ssicst.ads')
9.15 Ada.Strings.Unbounded.Text_IO (`a-suteio.ads')
9.16 Ada.Strings.Wide_Unbounded.Wide_Text_IO (`a-swuwti.ads')
9.17 Ada.Strings.Wide_Wide_Unbounded.Wide_Wide_Text_IO (`a-szuzti.ads')
9.18 Ada.Text_IO.C_Streams (`a-tiocst.ads')
9.19 Ada.Wide_Characters.Unicode (`a-wichun.ads')
9.20 Ada.Wide_Text_IO.C_Streams (`a-wtcstr.ads')
9.21 Ada.Wide_Wide_Characters.Unicode (`a-zchuni.ads')
9.22 Ada.Wide_Wide_Text_IO.C_Streams (`a-ztcstr.ads')
9.23 GNAT.Altivec (`g-altive.ads')
9.24 GNAT.Altivec.Conversions (`g-altcon.ads')
9.25 GNAT.Altivec.Vector_Operations (`g-alveop.ads')
9.26 GNAT.Altivec.Vector_Types (`g-alvety.ads')
9.27 GNAT.Altivec.Vector_Views (`g-alvevi.ads')
9.28 GNAT.Array_Split (`g-arrspl.ads')
9.29 GNAT.AWK (`g-awk.ads')
9.30 GNAT.Bounded_Buffers (`g-boubuf.ads')
9.31 GNAT.Bounded_Mailboxes (`g-boumai.ads')
9.32 GNAT.Bubble_Sort (`g-bubsor.ads')
9.33 GNAT.Bubble_Sort_A (`g-busora.ads')
9.34 GNAT.Bubble_Sort_G (`g-busorg.ads')
9.35 GNAT.Byte_Order_Mark (`g-byorma.ads')
9.36 GNAT.Byte_Swapping (`g-bytswa.ads')
9.37 GNAT.Calendar (`g-calend.ads')
9.38 GNAT.Calendar.Time_IO (`g-catiio.ads')
9.40 GNAT.Case_Util (`g-casuti.ads')
9.41 GNAT.CGI (`g-cgi.ads')
9.42 GNAT.CGI.Cookie (`g-cgicoo.ads')
9.43 GNAT.CGI.Debug (`g-cgideb.ads')
9.44 GNAT.Command_Line (`g-comlin.ads')
9.45 GNAT.Compiler_Version (`g-comver.ads')
9.46 GNAT.Ctrl_C (`g-ctrl_c.ads')
9.39 GNAT.CRC32 (`g-crc32.ads')
9.47 GNAT.Current_Exception (`g-curexc.ads')
9.48 GNAT.Debug_Pools (`g-debpoo.ads')
9.49 GNAT.Debug_Utilities (`g-debuti.ads')
9.50 GNAT.Decode_String (`g-decstr.ads')
9.51 GNAT.Decode_UTF8_String (`g-deutst.ads')
9.52 GNAT.Directory_Operations (`g-dirope.ads')
9.53 GNAT.Directory_Operations.Iteration (`g-diopit.ads')
9.54 GNAT.Dynamic_HTables (`g-dynhta.ads')
9.55 GNAT.Dynamic_Tables (`g-dyntab.ads')
9.56 GNAT.Encode_String (`g-encstr.ads')
9.57 GNAT.Encode_UTF8_String (`g-enutst.ads')
9.58 GNAT.Exception_Actions (`g-excact.ads')
9.59 GNAT.Exception_Traces (`g-exctra.ads')
9.60 GNAT.Exceptions (`g-expect.ads')
9.61 GNAT.Expect (`g-expect.ads')
9.62 GNAT.Float_Control (`g-flocon.ads')
9.63 GNAT.Heap_Sort (`g-heasor.ads')
9.64 GNAT.Heap_Sort_A (`g-hesora.ads')
9.65 GNAT.Heap_Sort_G (`g-hesorg.ads')
9.66 GNAT.HTable (`g-htable.ads')
9.67 GNAT.IO (`g-io.ads')
9.68 GNAT.IO_Aux (`g-io_aux.ads')
9.69 GNAT.Lock_Files (`g-locfil.ads')
9.70 GNAT.MD5 (`g-md5.ads')
9.71 GNAT.Memory_Dump (`g-memdum.ads')
9.72 GNAT.Most_Recent_Exception (`g-moreex.ads')
9.73 GNAT.OS_Lib (`g-os_lib.ads')
9.74 GNAT.Perfect_Hash_Generators (`g-pehage.ads')
9.75 GNAT.Random_Numbers (`g-rannum.ads')
9.76 GNAT.Regexp (`g-regexp.ads')
9.77 GNAT.Registry (`g-regist.ads')
9.78 GNAT.Regpat (`g-regpat.ads')
9.79 GNAT.Secondary_Stack_Info (`g-sestin.ads')
9.80 GNAT.Semaphores (`g-semaph.ads')
9.81 GNAT.Serial_Communications (`g-sercom.ads')
9.82 GNAT.SHA1 (`g-sha1.ads')
9.83 GNAT.Signals (`g-signal.ads')
9.84 GNAT.Sockets (`g-socket.ads')
9.85 GNAT.Source_Info (`g-souinf.ads')
9.86 GNAT.Spelling_Checker (`g-speche.ads')
9.87 GNAT.Spelling_Checker_Generic (`g-spchge.ads')
9.88 GNAT.Spitbol.Patterns (`g-spipat.ads')
9.89 GNAT.Spitbol (`g-spitbo.ads')
9.90 GNAT.Spitbol.Table_Boolean (`g-sptabo.ads')
9.91 GNAT.Spitbol.Table_Integer (`g-sptain.ads')
9.92 GNAT.Spitbol.Table_VString (`g-sptavs.ads')
9.93 GNAT.Strings (`g-string.ads')
9.94 GNAT.String_Split (`g-strspl.ads')
9.95 GNAT.Table (`g-table.ads')
9.96 GNAT.Task_Lock (`g-tasloc.ads')
9.98 GNAT.Threads (`g-thread.ads')
9.97 GNAT.Time_Stamp (`g-timsta.ads')
9.99 GNAT.Traceback (`g-traceb.ads')
9.100 GNAT.Traceback.Symbolic (`g-trasym.ads')
9.101 GNAT.UTF_32 (`g-table.ads')
9.102 GNAT.Wide_Spelling_Checker (`g-u3spch.ads')
9.103 GNAT.Wide_Spelling_Checker (`g-wispch.ads')
9.104 GNAT.Wide_String_Split (`g-wistsp.ads')
9.105 GNAT.Wide_Wide_Spelling_Checker (`g-zspche.ads')
9.106 GNAT.Wide_Wide_String_Split (`g-zistsp.ads')
9.107 Interfaces.C.Extensions (`i-cexten.ads')
9.108 Interfaces.C.Streams (`i-cstrea.ads')
9.109 Interfaces.CPP (`i-cpp.ads')
9.110 Interfaces.Packed_Decimal (`i-pacdec.ads')
9.111 Interfaces.VxWorks (`i-vxwork.ads')
9.112 Interfaces.VxWorks.IO (`i-vxwoio.ads')
9.113 System.Address_Image (`s-addima.ads')
9.114 System.Assertions (`s-assert.ads')
9.115 System.Memory (`s-memory.ads')
9.116 System.Partition_Interface (`s-parint.ads')
9.117 System.Pool_Global (`s-pooglo.ads')
9.118 System.Pool_Local (`s-pooloc.ads')
9.119 System.Restrictions (`s-restri.ads')
9.120 System.Rident (`s-rident.ads')
9.121 System.Task_Info (`s-tasinf.ads')
9.122 System.Wch_Cnv (`s-wchcnv.ads')
9.123 System.Wch_Con (`s-wchcon.ads')

9.1 Ada.Characters.Latin_9 (`a-chlat9.ads')

This child of Ada.Characters provides a set of definitions corresponding to those in the RM-defined package Ada.Characters.Latin_1 but with the few modifications required for Latin-9 The provision of such a package is specifically authorized by the Ada Reference Manual (RM A.3.3(27)).

9.2 Ada.Characters.Wide_Latin_1 (`a-cwila1.ads')

This child of Ada.Characters provides a set of definitions corresponding to those in the RM-defined package Ada.Characters.Latin_1 but with the types of the constants being Wide_Character instead of Character. The provision of such a package is specifically authorized by the Ada Reference Manual (RM A.3.3(27)).

9.3 Ada.Characters.Wide_Latin_9 (`a-cwila1.ads')

This child of Ada.Characters provides a set of definitions corresponding to those in the GNAT defined package Ada.Characters.Latin_9 but with the types of the constants being Wide_Character instead of Character. The provision of such a package is specifically authorized by the Ada Reference Manual (RM A.3.3(27)).

9.4 Ada.Characters.Wide_Wide_Latin_1 (`a-chzla1.ads')

This child of Ada.Characters provides a set of definitions corresponding to those in the RM-defined package Ada.Characters.Latin_1 but with the types of the constants being Wide_Wide_Character instead of Character. The provision of such a package is specifically authorized by the Ada Reference Manual (RM A.3.3(27)).

9.5 Ada.Characters.Wide_Wide_Latin_9 (`a-chzla9.ads')

This child of Ada.Characters provides a set of definitions corresponding to those in the GNAT defined package Ada.Characters.Latin_9 but with the types of the constants being Wide_Wide_Character instead of Character. The provision of such a package is specifically authorized by the Ada Reference Manual (RM A.3.3(27)).

9.6 Ada.Command_Line.Environment (`a-colien.ads')

This child of Ada.Command_Line provides a mechanism for obtaining environment values on systems where this concept makes sense.

9.7 Ada.Command_Line.Remove (`a-colire.ads')

This child of Ada.Command_Line provides a mechanism for logically removing arguments from the argument list. Once removed, an argument is not visible to further calls on the subprograms in Ada.Command_Line will not see the removed argument.

9.8 Ada.Command_Line.Response_File (`a-clrefi.ads')

This child of Ada.Command_Line provides a mechanism facilities for getting command line arguments from a text file, called a "response file". Using a response file allow passing a set of arguments to an executable longer than the maximum allowed by the system on the command line.

9.9 Ada.Direct_IO.C_Streams (`a-diocst.ads')

This package provides subprograms that allow interfacing between C streams and Direct_IO. The stream identifier can be extracted from a file opened on the Ada side, and an Ada file can be constructed from a stream opened on the C side.

9.10 Ada.Exceptions.Is_Null_Occurrence (`a-einuoc.ads')

This child subprogram provides a way of testing for the null exception occurrence (Null_Occurrence) without raising an exception.

9.11 Ada.Exceptions.Last_Chance_Handler (`a-elchha.ads')

This child subprogram is used for handling otherwise unhandled exceptions (hence the name last chance), and perform clean ups before terminating the program. Note that this subprogram never returns.

9.12 Ada.Exceptions.Traceback (`a-exctra.ads')

This child package provides the subprogram (Tracebacks) to give a traceback array of addresses based on an exception occurrence.

9.13 Ada.Sequential_IO.C_Streams (`a-siocst.ads')

This package provides subprograms that allow interfacing between C streams and Sequential_IO. The stream identifier can be extracted from a file opened on the Ada side, and an Ada file can be constructed from a stream opened on the C side.

9.14 Ada.Streams.Stream_IO.C_Streams (`a-ssicst.ads')

This package provides subprograms that allow interfacing between C streams and Stream_IO. The stream identifier can be extracted from a file opened on the Ada side, and an Ada file can be constructed from a stream opened on the C side.

9.15 Ada.Strings.Unbounded.Text_IO (`a-suteio.ads')

This package provides subprograms for Text_IO for unbounded strings, avoiding the necessity for an intermediate operation with ordinary strings.

9.16 Ada.Strings.Wide_Unbounded.Wide_Text_IO (`a-swuwti.ads')

This package provides subprograms for Text_IO for unbounded wide strings, avoiding the necessity for an intermediate operation with ordinary wide strings.

9.17 Ada.Strings.Wide_Wide_Unbounded.Wide_Wide_Text_IO (`a-szuzti.ads')

This package provides subprograms for Text_IO for unbounded wide wide strings, avoiding the necessity for an intermediate operation with ordinary wide wide strings.

9.18 Ada.Text_IO.C_Streams (`a-tiocst.ads')

This package provides subprograms that allow interfacing between C streams and Text_IO. The stream identifier can be extracted from a file opened on the Ada side, and an Ada file can be constructed from a stream opened on the C side.

9.19 Ada.Wide_Characters.Unicode (`a-wichun.ads')

This package provides subprograms that allow categorization of Wide_Character values according to Unicode categories.

9.20 Ada.Wide_Text_IO.C_Streams (`a-wtcstr.ads')

This package provides subprograms that allow interfacing between C streams and Wide_Text_IO. The stream identifier can be extracted from a file opened on the Ada side, and an Ada file can be constructed from a stream opened on the C side.

9.21 Ada.Wide_Wide_Characters.Unicode (`a-zchuni.ads')

This package provides subprograms that allow categorization of Wide_Wide_Character values according to Unicode categories.

9.22 Ada.Wide_Wide_Text_IO.C_Streams (`a-ztcstr.ads')

This package provides subprograms that allow interfacing between C streams and Wide_Wide_Text_IO. The stream identifier can be extracted from a file opened on the Ada side, and an Ada file can be constructed from a stream opened on the C side.

9.23 GNAT.Altivec (`g-altive.ads')

This is the root package of the GNAT AltiVec binding. It provides definitions of constants and types common to all the versions of the binding.

9.24 GNAT.Altivec.Conversions (`g-altcon.ads')

This package provides the Vector/View conversion routines.

9.25 GNAT.Altivec.Vector_Operations (`g-alveop.ads')

This package exposes the Ada interface to the AltiVec operations on vector objects. A soft emulation is included by default in the GNAT library. The hard binding is provided as a separate package. This unit is common to both bindings.

9.26 GNAT.Altivec.Vector_Types (`g-alvety.ads')

This package exposes the various vector types part of the Ada binding to AltiVec facilities.

9.27 GNAT.Altivec.Vector_Views (`g-alvevi.ads')

This package provides public 'View' data types from/to which private vector representations can be converted via GNAT.Altivec.Conversions. This allows convenient access to individual vector elements and provides a simple way to initialize vector objects.

9.28 GNAT.Array_Split (`g-arrspl.ads')

Useful array-manipulation routines: given a set of separators, split an array wherever the separators appear, and provide direct access to the resulting slices.

9.29 GNAT.AWK (`g-awk.ads')

Provides AWK-like parsing functions, with an easy interface for parsing one or more files containing formatted data. The file is viewed as a database where each record is a line and a field is a data element in this line.

9.30 GNAT.Bounded_Buffers (`g-boubuf.ads')

Provides a concurrent generic bounded buffer abstraction. Instances are useful directly or as parts of the implementations of other abstractions, such as mailboxes.

9.31 GNAT.Bounded_Mailboxes (`g-boumai.ads')

Provides a thread-safe asynchronous intertask mailbox communication facility.

9.32 GNAT.Bubble_Sort (`g-bubsor.ads')

Provides a general implementation of bubble sort usable for sorting arbitrary data items. Exchange and comparison procedures are provided by passing access-to-procedure values.

9.33 GNAT.Bubble_Sort_A (`g-busora.ads')

Provides a general implementation of bubble sort usable for sorting arbitrary data items. Move and comparison procedures are provided by passing access-to-procedure values. This is an older version, retained for compatibility. Usually GNAT.Bubble_Sort will be preferable.

9.34 GNAT.Bubble_Sort_G (`g-busorg.ads')

Similar to Bubble_Sort_A except that the move and sorting procedures are provided as generic parameters, this improves efficiency, especially if the procedures can be inlined, at the expense of duplicating code for multiple instantiations.

9.35 GNAT.Byte_Order_Mark (`g-byorma.ads')

Provides a routine which given a string, reads the start of the string to see whether it is one of the standard byte order marks (BOM's) which signal the encoding of the string. The routine includes detection of special XML sequences for various UCS input formats.

9.36 GNAT.Byte_Swapping (`g-bytswa.ads')

General routines for swapping the bytes in 2-, 4-, and 8-byte quantities. Machine-specific implementations are available in some cases.

9.37 GNAT.Calendar (`g-calend.ads')

Extends the facilities provided by Ada.Calendar to include handling of days of the week, an extended Split and Time_Of capability. Also provides conversion of Ada.Calendar.Time values to and from the C timeval format.

9.38 GNAT.Calendar.Time_IO (`g-catiio.ads')

9.39 GNAT.CRC32 (`g-crc32.ads')

This package implements the CRC-32 algorithm. For a full description of this algorithm see "Computation of Cyclic Redundancy Checks via Table Look-Up", Communications of the ACM, Vol. 31 No. 8, pp. 1008-1013, Aug. 1988. Sarwate, D.V.

9.40 GNAT.Case_Util (`g-casuti.ads')

A set of simple routines for handling upper and lower casing of strings without the overhead of the full casing tables in Ada.Characters.Handling.

9.41 GNAT.CGI (`g-cgi.ads')

This is a package for interfacing a GNAT program with a Web server via the Common Gateway Interface (CGI). Basically this package parses the CGI parameters, which are a set of key/value pairs sent by the Web server. It builds a table whose index is the key and provides some services to deal with this table.

9.42 GNAT.CGI.Cookie (`g-cgicoo.ads')

This is a package to interface a GNAT program with a Web server via the Common Gateway Interface (CGI). It exports services to deal with Web cookies (piece of information kept in the Web client software).

9.43 GNAT.CGI.Debug (`g-cgideb.ads')

This is a package to help debugging CGI (Common Gateway Interface) programs written in Ada.

9.44 GNAT.Command_Line (`g-comlin.ads')

Provides a high level interface to Ada.Command_Line facilities, including the ability to scan for named switches with optional parameters and expand file names using wild card notations.

9.45 GNAT.Compiler_Version (`g-comver.ads')

Provides a routine for obtaining the version of the compiler used to compile the program. More accurately this is the version of the binder used to bind the program (this will normally be the same as the version of the compiler if a consistent tool set is used to compile all units of a partition).

9.46 GNAT.Ctrl_C (`g-ctrl_c.ads')

Provides a simple interface to handle Ctrl-C keyboard events.

9.47 GNAT.Current_Exception (`g-curexc.ads')

Provides access to information on the current exception that has been raised without the need for using the Ada 95 / Ada 2005 exception choice parameter specification syntax. This is particularly useful in simulating typical facilities for obtaining information about exceptions provided by Ada 83 compilers.

9.48 GNAT.Debug_Pools (`g-debpoo.ads')

Provide a debugging storage pools that helps tracking memory corruption problems. See section `The GNAT Debug Pool Facility' in GNAT Pro User's Guide.

9.49 GNAT.Debug_Utilities (`g-debuti.ads')

Provides a few useful utilities for debugging purposes, including conversion to and from string images of address values. Supports both C and Ada formats for hexadecimal literals.

9.50 GNAT.Decode_String (`g-decstr.ads')

A generic package providing routines for decoding wide character and wide wide character strings encoded as sequences of 8-bit characters using a specified encoding method. Includes validation routines, and also routines for stepping to next or previous encoded character in an encoded string. Useful in conjunction with Unicode character coding. Note there is a preinstantiation for UTF-8. See next entry.

9.51 GNAT.Decode_UTF8_String (`g-deutst.ads')

A preinstantiation of GNAT.Decode_Strings for UTF-8 encoding.

9.52 GNAT.Directory_Operations (`g-dirope.ads')

Provides a set of routines for manipulating directories, including changing the current directory, making new directories, and scanning the files in a directory.

9.53 GNAT.Directory_Operations.Iteration (`g-diopit.ads')

A child unit of GNAT.Directory_Operations providing additional operations for iterating through directories.

9.54 GNAT.Dynamic_HTables (`g-dynhta.ads')

A generic implementation of hash tables that can be used to hash arbitrary data. Provided in two forms, a simple form with built in hash functions, and a more complex form in which the hash function is supplied.

This package provides a facility similar to that of GNAT.HTable, except that this package declares a type that can be used to define dynamic instances of the hash table, while an instantiation of GNAT.HTable creates a single instance of the hash table.

9.55 GNAT.Dynamic_Tables (`g-dyntab.ads')

A generic package providing a single dimension array abstraction where the length of the array can be dynamically modified.

This package provides a facility similar to that of GNAT.Table, except that this package declares a type that can be used to define dynamic instances of the table, while an instantiation of GNAT.Table creates a single instance of the table type.

9.56 GNAT.Encode_String (`g-encstr.ads')

A generic package providing routines for encoding wide character and wide wide character strings as sequences of 8-bit characters using a specified encoding method. Useful in conjunction with Unicode character coding. Note there is a preinstantiation for UTF-8. See next entry.

9.57 GNAT.Encode_UTF8_String (`g-enutst.ads')

A preinstantiation of GNAT.Encode_Strings for UTF-8 encoding.

9.58 GNAT.Exception_Actions (`g-excact.ads')

Provides callbacks when an exception is raised. Callbacks can be registered for specific exceptions, or when any exception is raised. This can be used for instance to force a core dump to ease debugging.

9.59 GNAT.Exception_Traces (`g-exctra.ads')

Provides an interface allowing to control automatic output upon exception occurrences.

9.60 GNAT.Exceptions (`g-expect.ads')

Normally it is not possible to raise an exception with a message from a subprogram in a pure package, since the necessary types and subprograms are in Ada.Exceptions which is not a pure unit. GNAT.Exceptions provides a facility for getting around this limitation for a few predefined exceptions, and for example allow raising Constraint_Error with a message from a pure subprogram.

9.61 GNAT.Expect (`g-expect.ads')

Provides a set of subprograms similar to what is available with the standard Tcl Expect tool. It allows you to easily spawn and communicate with an external process. You can send commands or inputs to the process, and compare the output with some expected regular expression. Currently GNAT.Expect is implemented on all native GNAT ports except for OpenVMS. It is not implemented for cross ports, and in particular is not implemented for VxWorks or LynxOS.

9.62 GNAT.Float_Control (`g-flocon.ads')

Provides an interface for resetting the floating-point processor into the mode required for correct semantic operation in Ada. Some third party library calls may cause this mode to be modified, and the Reset procedure in this package can be used to reestablish the required mode.

9.63 GNAT.Heap_Sort (`g-heasor.ads')

Provides a general implementation of heap sort usable for sorting arbitrary data items. Exchange and comparison procedures are provided by passing access-to-procedure values. The algorithm used is a modified heap sort that performs approximately N*log(N) comparisons in the worst case.

9.64 GNAT.Heap_Sort_A (`g-hesora.ads')

Provides a general implementation of heap sort usable for sorting arbitrary data items. Move and comparison procedures are provided by passing access-to-procedure values. The algorithm used is a modified heap sort that performs approximately N*log(N) comparisons in the worst case. This differs from GNAT.Heap_Sort in having a less convenient interface, but may be slightly more efficient.

9.65 GNAT.Heap_Sort_G (`g-hesorg.ads')

Similar to Heap_Sort_A except that the move and sorting procedures are provided as generic parameters, this improves efficiency, especially if the procedures can be inlined, at the expense of duplicating code for multiple instantiations.

9.66 GNAT.HTable (`g-htable.ads')

A generic implementation of hash tables that can be used to hash arbitrary data. Provides two approaches, one a simple static approach, and the other allowing arbitrary dynamic hash tables.

9.67 GNAT.IO (`g-io.ads')

A simple preelaborable input-output package that provides a subset of simple Text_IO functions for reading characters and strings from Standard_Input, and writing characters, strings and integers to either Standard_Output or Standard_Error.

9.68 GNAT.IO_Aux (`g-io_aux.ads')

Provides some auxiliary functions for use with Text_IO, including a test for whether a file exists, and functions for reading a line of text.

9.69 GNAT.Lock_Files (`g-locfil.ads')

Provides a general interface for using files as locks. Can be used for providing program level synchronization.

9.70 GNAT.MD5 (`g-md5.ads')

Implements the MD5 Message-Digest Algorithm as described in RFC 1321.