【RT-Thread学习笔记】使用scons命令生成静态库

嵌入式物联网开发 2022-07-27 6005

描述

1 问题来源

本问题来源于RT-Thread的技术论坛的一个常见问题，当时我回答了这个问题，很荣幸拿了一个最佳答案，为了能够再次消化并进行知识点沉淀，我把这个问题再次抛到这里。原问题，请戳这里：scons 命令buildlib使用方法

2 实践分析

2.1 不懂就要问

既然不知道怎么用scons，那么我们先看到它的帮助信息，以下命令在scons的主目录执行，即可以找到Sconscript的目录下执行：

rt-thread/bsp/qemu-vexpress-a9$ scons -h
scons: Reading SConscript files ...
drivers/SConscript
applications/SConscript
[, , ]
scons: done reading SConscript files.
usage: scons [OPTION] [TARGET] ...
SCons Options:
-b, -d, -e, -m, -S, -t, -w, --environment-overrides, --no-keep-going,
--no-print-directory, --print-directory, --stop, --touch
Ignored for compatibility.
-c, --clean, --remove Remove specified targets and dependencies.
-C DIR, --directory=DIR Change to DIR before doing anything.
--cache-debug=FILE Print CacheDir debug info to FILE.
--cache-disable, --no-cache
Do not retrieve built targets from CacheDir.
--cache-force, --cache-populate
Copy already-built targets into the CacheDir.
--cache-readonly Do not update CacheDir with built targets.
--cache-show Print build actions for files from CacheDir.
--config=MODE Controls Configure subsystem: auto, force,
cache.
-D Search up directory tree for SConstruct,
build all Default() targets.
--debug=TYPE Print various types of debugging information:
count, duplicate, explain, findlibs, includes,
memoizer, memory, objects, pdb, prepare,
presub, stacktrace, time, action-timestamps.
--diskcheck=TYPE Enable specific on-disk checks.
--duplicate=DUPLICATE Set the preferred duplication methods. Must be
one of hard-soft-copy, soft-hard-copy,
hard-copy, soft-copy, copy
--enable-virtualenv Import certain virtualenv variables to SCons
-f FILE, --file=FILE, --makefile=FILE, --sconstruct=FILE
Read FILE as the top-level SConstruct file.
-h, --help Print defined help message, or this one.
-H, --help-options Print this message and exit.
-i, --ignore-errors Ignore errors from build actions.
-I DIR, --include-dir=DIR Search DIR for imported Python modules.
--ignore-virtualenv Do not import virtualenv variables to SCons
--implicit-cache Cache implicit dependencies
--implicit-deps-changed Ignore cached implicit dependencies.
--implicit-deps-unchanged Ignore changes in implicit dependencies.
--interact, --interactive Run in interactive mode.
-j N, --jobs=N Allow N jobs at once.
-k, --keep-going Keep going when a target can't be made.
--max-drift=N Set maximum system clock drift to N seconds.
--md5-chunksize=N Set chunk-size for MD5 signature computation to
N kilobytes.
-n, --no-exec, --just-print, --dry-run, --recon
Don't build; just print commands.
--no-site-dir Don't search or use the usual site_scons dir.
--profile=FILE Profile SCons and put results in FILE.
-q, --question Don't build; exit status says if up to date.
-Q Suppress "Reading/Building" progress messages.
--random Build dependencies in random order.
-s, --silent, --quiet Don't print commands.
--site-dir=DIR Use DIR instead of the usual site_scons dir.
--stack-size=N Set the stack size of the threads used to run
jobs to N kilobytes.
--taskmastertrace=FILE Trace Node evaluation to FILE.
--tree=OPTIONS Print a dependency tree in various formats: all,
derived, prune, status, linedraw.
-u, --up, --search-up Search up directory tree for SConstruct,
build targets at or below current directory.
-U Search up directory tree for SConstruct,
build Default() targets from local SConscript.
-v, --version Print the SCons version number and exit.
--warn=WARNING-SPEC, --warning=WARNING-SPEC
Enable or disable warnings.
-Y REPOSITORY, --repository=REPOSITORY, --srcdir=REPOSITORY
Search REPOSITORY for source and target files.
Local Options:
--dist make distribution
--dist-strip make distribution and strip useless files
--dist-ide make distribution for RT-Thread Studio IDE
--project-path=PROJECT-PATH
set dist-ide project output path
--project-name=PROJECT-NAME
set project name
--reset-project-config reset the project configurations to default
--cscope Build Cscope cross reference database. Requires
cscope installed.
--clang-analyzer Perform static analyze with Clang-analyzer.
Requires Clang installed. It is recommended to
use with scan-build like this: `scan-build
scons --clang-analyzer` If things goes well,
scan-build will instruct you to invoke
scan-view.
--buildlib=BUILDLIB building library of a component
--cleanlib clean up the library by --buildlib
--target=TARGET set target project: mdk/mdk4/mdk5/iar/vs/vsc/ua/
cdk/ses/makefile/eclipse/codelite/cmake
--stackanalysis thread stack static analysis
--genconfig Generate .config from rtconfig.h
--useconfig=USECONFIG make rtconfig.h from config file.
--verbose print verbose information during build
--menuconfig make menuconfig for RT-Thread BSP
--pyconfig Python GUI menuconfig for RT-Thread BSP
--pyconfig-silent Don`t show pyconfig window

精准匹配下：

rt-thread/bsp/qemu-vexpress-a9$ scons -h | grep buildlib
--buildlib=BUILDLIB building library of a component
--cleanlib clean up the library by --buildlib

2.2 实践出整理

从上面的帮助信息，我们已经找到关键信息了，我们来实践下：

rt-thread/bsp/qemu-vexpress-a9$ scons --buildlib=BUILDLIB
scons: Reading SConscript files ...
b''
drivers/SConscript
applications/SConscript
[, , ]
scons: done reading SConscript files.
scons: Building targets ...
scons: building associated VariantDir targets: build
scons: `.' is up to date.
scons: done building targets.

发现并没有生成，仔细一看，这个buildlib=后面跟的名称不是乱填的，是需要填写你当前目录下，已经使用scons语法配置好的组件，这个东西在scons里面是叫Group。通俗来说，就是使用buildlib，一个Gourp就可以生成一个库。我们再来实践下，以bsp/qemu-vexpress-a9的Application这个Group为例，在其applications目录有定义Sconsript:

那么就可以输入scons--buildlib=Applications

就可以将Applications那个group定义的C文件编译打包成一个静态库，输出也是位于bsp的目录中。

3 经验总结

任何命令行指令，千万不要放过它的help信息
scons 使用--buildlib=xxx轻松生存库文件，库名称为libxxx.a

4 更多分享

架构师李肯

一个专注于嵌入式IoT领域的架构师。有着近10年的嵌入式一线开发经验，深耕IoT领域多年，熟知IoT领域的业务发展，深度掌握IoT领域的相关技术栈，包括但不限于主流RTOS内核的实现及其移植、硬件驱动移植开发、网络通讯协议开发、编译构建原理及其实现、底层汇编及编译原理、编译优化及代码重构、主流IoT云平台的对接、嵌入式IoT系统的架构设计等等。拥有多项IoT领域的发明专利，热衷于技术分享，有多年撰写技术博客的经验积累，连续多月获得RT-Thread官方技术社区原创技术博文优秀奖，荣获CSDN博客专家、CSDN物联网领域优质创作者、2021年度CSDN&RT-Thread技术社区之星、RT-Thread官方嵌入式开源社区认证专家、RT-Thread 2021年度论坛之星TOP4、华为云云享专家（嵌入式物联网架构设计师）等荣誉。坚信【知识改变命运，技术改变世界】！

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