@setfilename gnat_ugn_unw.info
@end ifset
+@set FSFEDITION
+@set EDITION GNAT
+
+@ifset unw
+@set PLATFORM Unix and Windows
+@set FILE gnat_ugn_unw
+@end ifset
+
@ifset vms
-@settitle GNAT User's Guide for Native Platforms / OpenVMS Alpha
-@dircategory GNU Ada tools
-@direntry
-* GNAT User's Guide (gnat_ugn_vms) for Native Platforms / OpenVMS Alpha
-@end direntry
+@set PLATFORM OpenVMS Alpha
+@set FILE gnat_ugn_vms
@end ifset
-@ifset unw
-@settitle GNAT User's Guide for Native Platforms / Unix and Windows
+
+
+@settitle @value{EDITION} User's Guide for Native Platforms / @value{PLATFORM}
+@dircategory GNU Ada tools
@direntry
-* GNAT User's Guide (gnat_ugn_unw) for Native Platforms / Unix and Windows
+* @value{EDITION} User's Guide (@value{FILE}) for Native Platforms / @value{PLATFORM}
@end direntry
-@end ifset
@include gcc-common.texi
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
-@ifset vms
-``GNAT User's Guide for Native Platforms / OpenVMS Alpha'',
-@end ifset
-@ifset unw
-``GNAT User's Guide for Native Platforms / Unix and Windows'',
-@end ifset
+``GNAT User's Guide for Native Platforms / @value{PLATFORM}'',
and with no Back-Cover Texts.
A copy of the license is included in the section entitled
``GNU Free Documentation License''.
@titlepage
-@title GNAT User's Guide
+@title @value{EDITION} User's Guide
@center @titlefont{for Native Platforms}
@sp 1
@flushright
-@ifset unw
-@titlefont{@i{Unix and Windows}}
-@end ifset
-@ifset vms
-@titlefont{@i{OpenVMS Alpha}}
-@end ifset
+@titlefont{@i{@value{PLATFORM}}}
@end flushright
@sp 2
@ifnottex
@node Top, About This Guide, (dir), (dir)
-@top GNAT User's Guide
-
-@ifset vms
-@noindent
-GNAT User's Guide for Native Platforms / OpenVMS Alpha
-@end ifset
+@top @value{EDITION} User's Guide
-@ifset unw
@noindent
-GNAT User's Guide for Native Platforms / Unix and Windows
-@end ifset
+@value{EDITION} User's Guide for Native Platforms / @value{PLATFORM}
@noindent
GNAT, The GNU Ada 95 Compiler@*
@noindent
@ifset vms
-This guide describes the use of of GNAT, a full language compiler for the Ada
+This guide describes the use of of @value{EDITION},
+a full language compiler for the Ada
95 programming language, implemented on HP OpenVMS Alpha platforms.
@end ifset
@ifclear vms
-This guide describes the use of GNAT, a compiler and software development
+This guide describes the use of @value{EDITION},
+a compiler and software development
toolset for the full Ada 95 programming language.
@end ifclear
It describes the features of the compiler and tools, and details
how to use them to build Ada 95 applications.
+@ifset PROEDITION
+For ease of exposition, ``GNAT Pro'' will be referred to simply as
+``GNAT'' in the remainder of this document.
+@end ifset
+
+
+
@menu
* What This Guide Contains::
* What You Should Know before Reading This Guide::
Fixed-point type declarations with a null range
@item
+Direct_IO or Sequential_IO instantiated with a type that has access values
+
+@item
Variables that are never assigned a value
@item
@end itemize
@noindent
-Note that the compiler is invoked using the command
-@command{^gnatmake -f -u -c^gnatmake -f -u -c^}.
+(note that the compiler is invoked using the command
+@command{^gnatmake -f -u -c^gnatmake -f -u -c^}).
+
+@noindent
+On non VMS platforms, between @command{gnat} and the command, two
+special switches may be used:
+
+@itemize @bullet
+@item
+@command{-v} to display the invocation of the tool.
+@item
+@command{-dn} to prevent the @command{gnat} driver from removing
+the temporary files it has created. These temporary files are
+configuration files and temporary file list files.
+@end itemize
@noindent
The command may be followed by switches and arguments for the invoked
* Introduction to Dynamic Link Libraries (DLLs)::
* Using DLLs with GNAT::
* Building DLLs with GNAT::
+* Building DLLs with GNAT Project files::
+* Building DLLs with gnatdll::
* GNAT and Windows Resources::
* Debugging a DLL::
* GNAT and COM/DCOM Objects::
To illustrate the remainder of this section, suppose that an application
wants to use the services of a DLL @file{API.dll}. To use the services
-provided by @file{API.dll} you must statically link against an import
-library which contains a jump table with an entry for each routine and
-variable exported by the DLL. In the Microsoft world this import library is
-called @file{API.lib}. When using GNAT this import library is called either
-@file{libAPI.a} or @file{libapi.a} (names are case insensitive).
-
-After you have statically linked your application with the import library
+provided by @file{API.dll} you must statically link against the DLL or
+an import library which contains a jump table with an entry for each
+routine and variable exported by the DLL. In the Microsoft world this
+import library is called @file{API.lib}. When using GNAT this import
+library is called either @file{libAPI.a} or @file{libapi.a} (names are
+case insensitive).
+
+After you have linked your application with the DLL or the import library
and you run your application, here is what happens:
@enumerate
@end itemize
@item
-The entries in the @file{libAPI.a} or @file{API.lib} jump table which is
-part of your application are initialized with the addresses of the routines
-and variables in @file{API.dll}.
+The entries in the jump table (from the import library @file{libAPI.a}
+or @file{API.lib} or automatically created when linking against a DLL)
+which is part of your application are initialized with the addresses
+of the routines and variables in @file{API.dll}.
@item
If present in @file{API.dll}, routines @code{DllMain} or
As a side note, an interesting difference between Microsoft DLLs and
Unix shared libraries, is the fact that on most Unix systems all public
routines are exported by default in a Unix shared library, while under
-Windows the exported routines must be listed explicitly in a definition
-file (@pxref{The Definition File}).
+Windows it is possible (but not required) to list exported routines in
+a definition file (@pxref{The Definition File}).
@node Using DLLs with GNAT
@section Using DLLs with GNAT
mentioned an import library is a statically linked library containing the
import table which will be filled at load time to point to the actual
@file{API.dll} routines. Sometimes you don't have an import library for the
-DLL you want to use. The following sections will explain how to build one.
+DLL you want to use. The following sections will explain how to build
+one. Note that this is optional.
@item
The actual DLL, @file{API.dll}.
@noindent
If a Microsoft-style import library @file{API.lib} or a GNAT-style
import library @file{libAPI.a} is available with @file{API.dll} you
-can skip this section. Otherwise read on.
+can skip this section. You can also skip this section if
+@file{API.dll} is built with GNU tools as in this case it is possible
+to link directly against the DLL. Otherwise read on.
@node The Definition File
@subsubsection The Definition File
@section Building DLLs with GNAT
@cindex DLLs, building
+@noindent
+This section explain how to build DLLs using the GNAT built-in DLL
+support. With the following procedure it is straight forward to build
+and use DLLs with GNAT.
+
+@enumerate
+
+@item building object files
+
+The first step is to build all objects files that are to be included
+into the DLL. This is done by using the standard @code{gnatmake} tool.
+
+@item building the DLL
+
+To build the DLL you must use @code{gcc}'s @code{-shared}
+option. It is quite simple to use this method:
+
+@smallexample
+$ gcc -shared -o api.dll obj1.o obj2.o ...
+@end smallexample
+
+It is important to note that in this case all symbols found in the
+object files are automatically exported. It is possible to restrict
+the set of symbols to export by passing to @code{gcc} a definition
+file, @pxref{The Definition File}. For example:
+
+@smallexample
+$ gcc -shared -o api.dll api.def obj1.o obj2.o ...
+@end smallexample
+
+If you use a definition file you must export the elaboration procedures
+for every package that required one. Elaboration procedures are named
+using the package name followed by "_E".
+
+@item preparing DLL to be used
+
+For the DLL to be used by client programs the bodies must be hidden
+from it and the .ali set with read-only attribute. This is very important
+otherwise GNAT will recompile all packages and will not actually use
+the code in the DLL. For example:
+
+@smallexample
+$ mkdir apilib
+$ copy *.ads *.ali api.dll apilib
+$ attrib +R apilib\*.ali
+@end smallexample
+
+@end enumerate
+
+At this point it is possible to use the DLL by directly linking
+against it. Note that you must use the GNAT shared runtime when using
+GNAT shared libraries. This is achieved by using @code{-shared} binder's
+option.
+
+@smallexample
+$ gnatmake main -Iapilib -bargs -shared -largs -Lapilib -lAPI
+@end smallexample
+
+@node Building DLLs with GNAT Project files
+@section Building DLLs with GNAT Project files
+@cindex DLLs, building
+
+@noindent
+There is nothing specific to Windows in this area. @pxref{Library Projects}.
+
+@node Building DLLs with gnatdll
+@section Building DLLs with gnatdll
+@cindex DLLs, building
+
@menu
* Limitations When Using Ada DLLs from Ada::
* Exporting Ada Entities::
@end menu
@noindent
-This section explains how to build DLLs containing Ada code. These DLLs
-will be referred to as Ada DLLs in the remainder of this section.
+Note that it is prefered to use the built-in GNAT DLL support
+(@pxref{Building DLLs with GNAT}) or GNAT Project files
+(@pxref{Building DLLs with GNAT Project files}) to build DLLs.
+
+This section explains how to build DLLs containing Ada code using
+@code{gnatdll}. These DLLs will be referred to as Ada DLLs in the
+remainder of this section.
The steps required to build an Ada DLL that is to be used by Ada as well as
non-Ada applications are as follows:
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