android - 为 Android 构建 ImageMagick

Question

我正在使用https://github.com/lilac/Android-ImageMagick为 Android 构建 ImageMagick 库。当尝试 ndk-build ImageMagick 时，我最终遇到以下错误。

primary0:AndroidMagickActivity primary0$ ~/ndk/ndk-build 
SharedLibrary  : libandroid-magick.so
/Users/primary0/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/darwin-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/libcoders.a(jpeg.o): in function ReadJPEGImage:jni/../ndk-modules/ImageMagick-6.7.3-0/coders/jpeg.c:988: error: undefined reference to 'jpeg_std_error'
/Users/primary0/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/darwin-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/libcoders.a(jpeg.o): in function ReadJPEGImage:jni/../ndk-modules/ImageMagick-6.7.3-0/coders/jpeg.c:995: error: undefined reference to 'jpeg_destroy_decompress'
/Users/primary0/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/darwin-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/libcoders.a(jpeg.o): in function ReadJPEGImage:jni/../ndk-modules/ImageMagick-6.7.3-0/coders/jpeg.c:1004: error: undefined reference to 'jpeg_CreateDecompress'
/Users/primary0/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/darwin-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/libcoders.a(jpeg.o): in function ReadJPEGImage:jni/../ndk-modules/ImageMagick-6.7.3-0/coders/jpeg.c:1006: error: undefined reference to 'jpeg_set_marker_processor'
/Users/primary0/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/darwin-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/libcoders.a(jpeg.o): in function ReadJPEGImage:jni/../ndk-modules/ImageMagick-6.7.3-0/coders/jpeg.c:1007: error: undefined reference to 'jpeg_set_marker_processor'
/Users/primary0/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/darwin-x86/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/libcoders.a(jpeg.o): in function ReadJPEGImage:jni/../ndk-modules/ImageMagick-6.7.3-0/coders/jpeg.c:1008: error: undefined reference to 'jpeg_set_marker_
.
.
.
collect2: ld returned 1 exit status 
make: *** [obj/local/armeabi/libandroid-magick.so] Error 1
primary0:AndroidMagickActivity primary0$ 

定义错误中列出的常量的头文件包含jpeg.c

#include "jpeglib.h"

你们中有人知道为什么我收到 undefined reference 错误吗？

Answer 1

链接器不是在寻找“常量”，而是在寻找调用函数的跳转地址。您的代码显然使用了目标代码中不可用的函数。这可能有多种原因。您没有告诉编译器使用可用的库，或者(在您的情况下更有可能)您没有告诉编译器还需要为此共享对象编译jpeg.c。但如果不查看 makefile，就很难诊断。

简单看一下 git 存储库的 ndk-modules 文件夹，我感觉您需要构建多个模块。也许您只是以错误的顺序进行操作。首先尝试构建 jpeg。