windows下调试Android NDK [英] Debugging Android NDK, under windows

问题描述

我正在将一个复杂的 C 应用程序移植到 Android，作为一个 SO 库，包裹着薄 java 层.经过几个小时的麻烦，我在Android下编译了代码，但是当然，应用程序崩溃了:(

I am porting a complex C application to Android, as an SO library, wrapped with thin java layer. After few hours of hassle, i have the code compiling under Android, but of course, the application crashes :(

环顾四周，我了解到在 Android 下调试 C 应用程序的唯一方法是通过 gdb.由于我对 gdb 没有太多经验，有没有人可以分享一些见解?

After looking around, i understand the only way to debug C application under Android is by gdb. Since I don't have a lot of experience with gdb, any one out there can share some insights?

谁有windows下gdb的教程:)?

Anyone has a tutorial for gdb under windows :) ?

谢谢

推荐答案

对于更新版本的 NDK(我使用的是 r7c)，您可以通过构建调试版本

for a more recent version of NDK (I am using r7c), you can build debug version by

1. 将 android:debuggable="true" 标志添加到 AndroidManifest.xml
中的 标记
2. 使用 NDK_DEBUG=1 调用 ndk-build(如果使用 unix shell 运行 ndk-build，则不需要 NDK_DEBUG 标志)

1. add android:debuggable="true" flag to <Application> tag in AndroidManifest.xml
2. invoke ndk-build with NDK_DEBUG=1 (NDK_DEBUG flag not necessary if running ndk-build with unix shell)

在 Windows 上，事情会变得有点棘手，因为要使用 ndk-gdb，您仍然需要从 NDK r7c 开始的 bash(或 cygwin)，但要运行 ndk-build如果您使用任何预构建的静态库，在 cygwin bash 中会遇到权限问题

on Windows, things get a bit tricky because to use ndk-gdb, you still need bash (or cygwin) as of NDK r7c, yet ndk-build running in cygwin bash will run into permission problem if you ever use any of the pre-built static library

我在 windows 机器上的解决方案是

my solution on windows machine is

1. 在AndroidManifest.xml中的<application标签中添加android:debuggable="true"标志(同上)
2. 在 cmd(Windows 的命令提示符)中:使用 NDK_DEBUG=1
调用 ndk-build
3. 在 cygwin bash 中:运行 ndk-gdb

1. add android:debuggable="true" flag to <application tag in AndroidManifest.xml (same as above)
2. in cmd (windows' command prompt): invoke ndk-build with NDK_DEBUG=1
3. in cygwin bash: run ndk-gdb

为了快速初步调查原生so库，创建一个简单的活动，一键触发库入口功能，活动中的loadLibrary如下:

for quick initial investigation of native so library, create a simple activity with one button to trigger library entry function and loadLibrary in the activity like:

class MyActivity extends Activity {
    static {
       System.loadLibrary("mylibrary");
    }

    /* other functions like onCreate, etc... */

    public native void libfunc();

    public void onClick(View v){
       libfunc();
    }
}

所以当 gdb 启动时，实际加载了相关库，但您仍然可以在程序崩溃之前设置断点等；当你完成调试器的设置后，在 (gdb) 提示符下，输入 continue(或只是 'c')，然后点击按钮启动崩溃的程序并愉快地调试......

So when gdb starts, the library in question is actually loaded, yet you can still have time to set break points, etc before the program crashes; when you finish setting up the debugger, at (gdb) prompt, type continue (or just 'c'), then hit the button to start the crashing program and happy debugging...

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