1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
<?xml version='1.0'?>
<!--
SPDX-License-Identifier: MIT
Copyright The SCons Foundation
-->
<!DOCTYPE sconsdoc [
<!ENTITY % scons SYSTEM "../scons.mod">
%scons;
<!ENTITY % builders-mod SYSTEM "../generated/builders.mod">
%builders-mod;
<!ENTITY % functions-mod SYSTEM "../generated/functions.mod">
%functions-mod;
<!ENTITY % tools-mod SYSTEM "../generated/tools.mod">
%tools-mod;
<!ENTITY % variables-mod SYSTEM "../generated/variables.mod">
%variables-mod;
]>
<section id="sect-variant-examples"
xmlns="http://www.scons.org/dbxsd/v1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.scons.org/dbxsd/v1.0 http://www.scons.org/dbxsd/v1.0/scons.xsd">
<title>Variant Build Examples</title>
<para>
The &variant_dir; keyword argument of
the &SConscript; function provides everything
we need to show how easy it is to create
variant builds using &SCons;.
Suppose, for example, that we want to
build a program for both Windows and Linux platforms,
but that we want to build it in directory on a network share
with separate side-by-side build directories
for the Windows and Linux versions of the program.
We have to do a little bit of work to construct paths,
to make sure unwanted location dependencies don't creep in.
The top-relative path reference can be useful here.
To avoid writing conditional code based on platform,
we can build the <parameter>variant_dir</parameter>
path dynamically:
</para>
<scons_example name="variants_ex">
<file name="SConstruct" printme="1">
platform = ARGUMENTS.get('OS', Platform())
include = "#export/$PLATFORM/include"
lib = "#export/$PLATFORM/lib"
bin = "#export/$PLATFORM/bin"
env = Environment(
PLATFORM=platform,
BINDIR=bin,
INCDIR=include,
LIBDIR=lib,
CPPPATH=[include],
LIBPATH=[lib],
LIBS='world',
)
Export('env')
env.SConscript('src/SConscript', variant_dir='build/$PLATFORM')
</file>
<directory name="src"></directory>
<directory name="src/hello"></directory>
<directory name="src/world"></directory>
<file name="src/SConscript">
Import('env')
SConscript('hello/SConscript')
SConscript('world/SConscript')
</file>
<file name="src/hello/SConscript">
Import('env')
hello = env.Program('hello.c')
env.Install('$BINDIR', hello)
</file>
<file name="src/hello/hello.c">
#include "world.h"
int main(int argc, char *argv[]) { printf "hello.c\n"; world(); }
</file>
<file name="src/world/SConscript">
Import('env')
world = env.Library('world.c')
env.Install('$LIBDIR', world)
env.Install('$INCDIR', 'world.h')
</file>
<file name="src/world/world.h">
#define STRING "world.h"
extern int world();
</file>
<file name="src/world/world.c">
int world() { printf "world.c\n"; }
</file>
</scons_example>
<para>
This SConstruct file,
when run on a Linux system, yields:
</para>
<scons_output example="variants_ex" os="posix" suffix="1">
<scons_output_command>scons -Q OS=linux</scons_output_command>
</scons_output>
<para>
The same SConstruct file on Windows would build:
</para>
<scons_output example="variants_ex" os="win32" suffix="2">
<scons_output_command>scons -Q OS=windows</scons_output_command>
</scons_output>
<para>
In order to build several variants at once when using the
<parameter>variant_dir</parameter> argument to &SConscript;,
you can call the function repeatedely - this example
does so in a loop. Note that the &f-link-SConscript; trick of
passing a list of script files, or a list of source directories,
does not work with <parameter>variant_dir</parameter>,
&SCons; allows only a single &SConscript; to be given if
<parameter>variant_dir</parameter> is used.
</para>
<scons_example name="variants_ex2">
<file name="SConstruct" printme="1">
env = Environment(OS=ARGUMENTS.get('OS'))
for os in ['newell', 'post']:
SConscript('src/SConscript', variant_dir='build/' + os)
</file>
</scons_example>
<!--
<scons_output example="variants_ex2" suffix="1">
<scons_output_command>scons -Q</scons_output_command>
</scons_output>
-->
</section>
|
