|
1 /**************************************************************************** |
|
2 ** |
|
3 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). |
|
4 ** All rights reserved. |
|
5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
|
6 ** |
|
7 ** This file is part of the documentation of the Qt Toolkit. |
|
8 ** |
|
9 ** $QT_BEGIN_LICENSE:LGPL$ |
|
10 ** No Commercial Usage |
|
11 ** This file contains pre-release code and may not be distributed. |
|
12 ** You may use this file in accordance with the terms and conditions |
|
13 ** contained in the Technology Preview License Agreement accompanying |
|
14 ** this package. |
|
15 ** |
|
16 ** GNU Lesser General Public License Usage |
|
17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
|
18 ** General Public License version 2.1 as published by the Free Software |
|
19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
|
20 ** packaging of this file. Please review the following information to |
|
21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
|
22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
|
23 ** |
|
24 ** In addition, as a special exception, Nokia gives you certain additional |
|
25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
|
26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
|
27 ** |
|
28 ** If you have questions regarding the use of this file, please contact |
|
29 ** Nokia at qt-info@nokia.com. |
|
30 ** |
|
31 ** |
|
32 ** |
|
33 ** |
|
34 ** |
|
35 ** |
|
36 ** |
|
37 ** |
|
38 ** $QT_END_LICENSE$ |
|
39 ** |
|
40 ****************************************************************************/ |
|
41 |
|
42 /*! |
|
43 \page qt-embedded-crosscompiling.html |
|
44 |
|
45 \title Cross-Compiling Qt for Embedded Linux Applications |
|
46 \ingroup qt-embedded-linux |
|
47 |
|
48 Cross-compiling is the process of compiling an application on one |
|
49 machine, producing executable code for a different machine or |
|
50 device. To cross-compile a \l{Qt for Embedded Linux} application, |
|
51 use the following approach: |
|
52 |
|
53 \tableofcontents |
|
54 |
|
55 \note The cross-compiling procedure has the configuration |
|
56 process in common with the installation procedure; i.e., you might |
|
57 not necessarily have to perform all the mentioned actions |
|
58 depending on your current configuration. |
|
59 |
|
60 \section1 Step 1: Set the Cross-Compiler's Path |
|
61 |
|
62 Specify which cross-compiler to use by setting the \c PATH |
|
63 environment variable. For example, if the current shell is bash, |
|
64 ksh, zsh or sh: |
|
65 |
|
66 \snippet doc/src/snippets/code/doc_src_emb-crosscompiling.qdoc 0 |
|
67 |
|
68 \section1 Step 2: Create a Target Specific qmake Specification |
|
69 |
|
70 The qmake tool requires a platform and compiler specific \c |
|
71 qmake.conf file describing the various default values, to generate |
|
72 the appropriate Makefiles. The standard \l{Qt for Embedded Linux} |
|
73 distribution provides such files for several combinations of |
|
74 platforms and compilers. These files are located in the |
|
75 distribution's \c mkspecs/qws subdirectory. |
|
76 |
|
77 Each platform has a default specification. \l{Qt for Embedded Linux} will |
|
78 use the default specification for the current platform unless told |
|
79 otherwise. To override this behavior, you can use the \c configure |
|
80 script's \c -platform option to change the specification for the host |
|
81 platform (where compilation will take place). |
|
82 |
|
83 The \c configure script's \c -xplatform option is used to provide a |
|
84 specification for the target architecture (where the library will be |
|
85 deployed). |
|
86 |
|
87 For example, to cross-compile an application to run on a device with |
|
88 an ARM architecture, using the GCC toolchain, run the configure |
|
89 script at the command line in the following way: |
|
90 |
|
91 \snippet doc/src/snippets/code/doc_src_emb-crosscompiling.qdoc 1 |
|
92 |
|
93 If neither of the provided specifications fits your target device, |
|
94 you can create your own. To create a custom \c qmake.conf file, |
|
95 just copy and customize an already existing file. For example: |
|
96 |
|
97 \snippet doc/src/snippets/code/doc_src_emb-crosscompiling.qdoc 2 |
|
98 |
|
99 \note When defining a mkspec for a Linux target, the directory must |
|
100 be prefixed with "linux-". We recommend that you copy the entire |
|
101 directory. |
|
102 |
|
103 Note also that when providing you own qmake specifcation, you must |
|
104 use the \c configure script's \c -xplatform option to make |
|
105 \l{Qt for Embedded Linux} aware of the custom \c qmake.conf file. |
|
106 |
|
107 \section1 Step 3: Provide Architecture Specific Files |
|
108 |
|
109 Starting with Qt 4, all of Qt's implicitly shared classes can |
|
110 safely be copied across threads like any other value classes, |
|
111 i.e., they are fully reentrant. This is accomplished by |
|
112 implementing reference counting operations using atomic hardware |
|
113 instructions on all the different platforms supported by Qt. |
|
114 |
|
115 To support a new architecture, it is important to ensure that |
|
116 these platform-specific atomic operations are implemented in a |
|
117 corresponding header file (\c qatomic_ARCH.h), and that this file |
|
118 is located in Qt's \c src/corelib/arch directory. For example, the |
|
119 Intel 80386 implementation is located in \c |
|
120 src/corelib/arch/qatomic_i386.h. |
|
121 |
|
122 See the \l {Implementing Atomic Operations} documentation for |
|
123 details. |
|
124 |
|
125 \section1 Step 4: Provide Hardware Drivers |
|
126 |
|
127 Without the proper mouse and keyboard drivers, you will not be |
|
128 able to give any input to your application when it is installed on |
|
129 the target device. You must also ensure that the appropriate |
|
130 screen driver is present to make the server process able to put |
|
131 the application's widgets on screen. |
|
132 |
|
133 \l{Qt for Embedded Linux} provides several ready-made mouse, keyboard and |
|
134 screen drivers, see the \l{Qt for Embedded Linux Pointer Handling}{pointer |
|
135 handling}, \l{Qt for Embedded Linux Character Input}{character input} and |
|
136 \l{Qt for Embedded Linux Display Management}{display management} |
|
137 documentation for details. |
|
138 |
|
139 In addition, custom drivers can be added by deriving from the |
|
140 QWSMouseHandler, QWSKeyboardHandler and QScreen classes |
|
141 respectively, and by creating corresponding plugins to make use of |
|
142 Qt's plugin mechanism (dynamically loading the drivers into the |
|
143 server application at runtime). Note that the plugins must be |
|
144 located in a location where Qt will look for plugins, e.g., the |
|
145 standard \c plugin directory. |
|
146 |
|
147 See the \l {How to Create Qt Plugins} documentation and the \l |
|
148 {tools/plugandpaint}{Plug & Paint} example for details. |
|
149 |
|
150 \section1 Step 5: Build the Target Specific Executable |
|
151 |
|
152 Before building the executable, you must specify the target |
|
153 architecture as well as the target specific hardware drivers by |
|
154 running the \c configure script: |
|
155 |
|
156 \snippet doc/src/snippets/code/doc_src_emb-crosscompiling.qdoc 3 |
|
157 |
|
158 It is also important to make sure that all the third party |
|
159 libraries that the application and the Qt libraries require, are |
|
160 present in the tool chain. In particular, if the zlib and jpeg |
|
161 libraries are not available, they must be included by running the |
|
162 \c configure script with the \c -L and \c -I options. For example: |
|
163 |
|
164 \snippet doc/src/snippets/code/doc_src_emb-crosscompiling.qdoc 4 |
|
165 |
|
166 The JPEG source can be downloaded from \l http://www.ijg.org/. The |
|
167 \l{Qt for Embedded Linux} distribution includes a version of the zlib source |
|
168 that can be compiled into the Qt for Embedded Linux library. If integrators |
|
169 wish to use a later version of the zlib library, it can be |
|
170 downloaded from the \l http://www.gzip.org/zlib/ website. |
|
171 |
|
172 Then build the executable: |
|
173 |
|
174 \snippet doc/src/snippets/code/doc_src_emb-crosscompiling.qdoc 5 |
|
175 |
|
176 That's all. Your target specific executable is ready for deployment. |
|
177 |
|
178 \table 100% |
|
179 \row |
|
180 \o \bold {See also:} |
|
181 |
|
182 \l{Qt for Embedded Linux Architecture} and \l{Deploying Qt for Embedded Linux |
|
183 Applications}. |
|
184 \endtable |
|
185 */ |