#跟着小白一起学鸿蒙# [二]第一个OpenHarmony程序 原创 精华

作者：王石，胡瑞涛

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在#跟着小白一起学鸿蒙# [一]运行OpenHarmony章节我们学习了如何下载，编译，运行OpenHarmony，接下来我们来熟悉下OpenHarmony的编译框架和如果自己开发一个HelloWord程序。

简介

OpenHarmony的编译过程分析

graph LR
build.sh --> build.py --> hb --> gn
hb --> ninja
hb --> clang

名词解释

• gn： generate ninja工具，在out目录下生成ninja编译文件*.ninja，文件位置在prebuilts/build-tools/linux-x86目录里

  $ ./gn --help
  Commands (type "gn help <command>" for more help):
    analyze: Analyze which targets are affected by a list of files.
    args: Display or configure arguments declared by the build.
    check: Check header dependencies.
    clean: Cleans the output directory.
    desc: Show lots of insightful information about a target or config.
    format: Format .gn files.
    gen: Generate ninja files.
    help: Does what you think.
    ls: List matching targets.
    meta: List target metadata collection results.
    path: Find paths between two targets.
    refs: Find stuff referencing a target or file.
  ……
  

• ninja：构建工具，根据gn生成的*.ninja文件进行编译构建，文件位置在prebuilts/build-tools/linux-x86目录里

  ./ninja --help
  usage: ninja [options] [targets...]
  if targets are unspecified, builds the 'default' target (see manual).
  options:
    --version      print ninja version ("1.10.1")
    -v, --verbose  show all command lines while building
  
    -C DIR   change to DIR before doing anything else
    -f FILE  specify input build file [default=build.ninja]
  
    -j N     run N jobs in parallel (0 means infinity) [default=10 on this system]
    -k N     keep going until N jobs fail (0 means infinity) [default=1]
    -l N     do not start new jobs if the load average is greater than N
    -n       dry run (don't run commands but act like they succeeded)
  
    -d MODE  enable debugging (use '-d list' to list modes)
    -t TOOL  run a subtool (use '-t list' to list subtools)
      terminates toplevel options; further flags are passed to the tool
    -w FLAG  adjust warnings (use '-w list' to list warnings)
  

• clang：编译器，同gcc兼容

1. 查看.gn并增加应用输出

路径为：oh32/third_party/libuv/BUILD.gn，找到如下位置增加

//静态库
ohos_static_library("uv_static") {
    deps = [ ":libuv_source" ]
        public_configs = [ ":libuv_config" ]
        subsystem_name = "thirdparty"
        part_name = "libuv"
}
//动态库
ohos_shared_library("uv") {
    deps = [ ":libuv_source" ]
        public_configs = [ ":libuv_config" ]
        subsystem_name = "thirdparty"
        part_name = "libuv"
        if (is_ohos) {
            output_extension = "so"
        }
    install_images = [
        "system",
        "updater",
    ]
}
//增加的新应用
ohos_executable("helloworld") {
  sources = [ "helloword.c",]
}

2. 增加helloworld.c

在oh32/third_party/libuv目录下增加helloworld.c

3. 增加helloworld编译生成的入口

• 在test/xts/acts/graphic/BUILD.gn里增加deps，如下

  import("//build/ohos_var.gni")
  group("graphic") {
    testonly = true
    if (is_standard_system) {
      deps = [
        "webGL:webGL_hap_test",
        "windowStage:ActsWindowStageTest",
        "windowstandard:window_hap_test",
        "//third_party/libuv:helloworld", #引入helloworld程序编译
      ]
    } else {
      deps = [
        "appaccount:appaccount_hap",
        "osaccount:osaccount_hap",
      ]
    }
  }
  
  

• 源码根目录执行：

  ./build.sh --product-name rk3568
  

• 源码根目录执行：

  ./build.sh --product-name rk3568 --gn-args build_xts=true --build-target "acts" --gn-args is_standard_system=true
  
  

5. 编译完成后生成的第三方库验证程序helloworld使用流程

• runtest库文件会输出helloworld，路径为：out/rk3568/common/common

  ~/oh32/out/rk3568/common/common$ ls
  libc  libimagePixelmap.so  libnativerender.so  libsqlite.z.so  libteststring.so  libusb_shared.z.so  helloworld
  

• 使用方式如下：

  1. 拷贝helloworld到板子上
  hdc_std.exe file send helloworld /data/local/tmp
  //2. 登录板子，运行helloworld，如果第一次需要给权限
  pc端：hdc_std.exe shell
  板子：cd /data/local/tmp
  板子：chmod +x helloworld
  板子：./helloworld
  

• 结果

  #./helloworld
  
  hello world!#
  

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