无法链接到GraphicsMagik

Question

我试图建立一种依靠GraphicsMagick工具C++库中的小工具程序，但链接到库时，我得到了以下错误：

make all-recursive 
make[1]: Entering directory `/home/ale/sample' 
Making all in src 
make[2]: Entering directory `/home/ale/sample/src' 
g++ -g -O2 -o mysample mysample-a.o -L/usr/local/lib -lexiv2 -L/usr/local/lib -lGraphicsMagick++ -lGraphicsMagick  
/usr/local/lib/libGraphicsMagick.a(magick_libGraphicsMagick_la-png.o): In function `png_put_data': 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1171: undefined reference to `png_get_io_ptr' 
/usr/local/lib/libGraphicsMagick.a(magick_libGraphicsMagick_la-png.o): In function `PNGWarningHandler': 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1357: undefined reference to `png_error' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1361: undefined reference to `png_get_error_ptr' 
/usr/local/lib/libGraphicsMagick.a(magick_libGraphicsMagick_la-png.o): In function `PNGErrorHandler': 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1338: undefined reference to `png_get_error_ptr' 
/usr/local/lib/libGraphicsMagick.a(magick_libGraphicsMagick_la-png.o): In function `png_get_data': 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1060: undefined reference to `png_get_io_ptr' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1076: undefined reference to `png_warning' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1077: undefined reference to `png_error' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:1067: undefined reference to `png_warning' 
/usr/local/lib/libGraphicsMagick.a(magick_libGraphicsMagick_la-png.o): In function `png_write_raw_profile': 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:6243: undefined reference to `png_malloc' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:6253: undefined reference to `png_malloc' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:6254: undefined reference to `png_malloc' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:6281: undefined reference to `png_set_text' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:6282: undefined reference to `png_free' 
/home/ale/Downloads/GraphicsMagick-1.3.18/coders/png.c:6283: undefined reference to `png_free' 

为什么在/ usr库/ local/lib是指GraphicsMagick源代码（我已经构建并安装）？

Answer 1

错误说你也需要和libpng链接。

由于您已经使用调试符号构建了graphicsmagick，因此您的源代码相关的错误非常具有描述性。在发布版本中（或者如果您将调试符号从调试版本中剥离出来），您只会看到未定义的函数名称，而没有源代码引用它们的使用位置。