xcode MacOSX 下 libpng 的链接器错误
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Linker error with libpng under MacOSX
提问by Manlio
I'm working on MacOSX 10.7.2 and Xcode 4.2.1. I installed libpngusing port and I was trying to load a PNG image in my application, but I get linker errors:
我正在使用 MacOSX 10.7.2 和 Xcode 4.2.1。我libpng使用 port安装，并且试图在我的应用程序中加载 PNG 图像，但出现链接器错误：
Undefined symbols for architecture x86_64:
"_png_create_read_struct", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_create_info_struct", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_destroy_read_struct", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_set_longjmp_fn", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_init_io", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_set_sig_bytes", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_read_png", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_get_IHDR", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_get_rowbytes", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
"_png_get_rows", referenced from:
loadPngImage(char*, int&, int&, bool&, unsigned char**) in test.o
ld: symbol(s) not found for architecture x86_64
I included png.hin my project using
我包括png.h在我的项目中使用
#include "/usr/X11/include/png.h"
I know libpngis based on zlib, thus I have included -lzin "Other linker flags" but nothing changed.
我知道libpng基于zlib，因此我已将其包含-lz在“其他链接器标志”中，但没有任何改变。
Any suggestions on how to make it work?
有关如何使其工作的任何建议？
采纳答案by Manlio
I solved with a manual installation of libpng:
我通过手动安装解决了libpng：
- download the source from official web site
in Terminal, go in the downloaded folder and launch
cp ./scripts/makefile.darwin makefile make sudo make install make cleanif it doesn't work (as in my case) open
makefilewith TextEdit (or equivalent) and change lineARCH="-arch i386 -arch x86_64"in
ARCH=-arch x86_64(assuming, of course, your system is 64 bit).
- 从官网下载源码
在终端中，进入下载的文件夹并启动
cp ./scripts/makefile.darwin makefile make sudo make install make clean如果它不起作用（如我的情况）
makefile用 TextEdit（或等效的）打开并更改行ARCH="-arch i386 -arch x86_64"在
ARCH=-arch x86_64（当然，假设您的系统是 64 位）。
It may not be enough. Xcode was still unable to find the library. I solved using
这可能还不够。Xcode 仍然无法找到该库。我解决了使用
cd /usr/local/lib
sudo ln -s libpng15.dylib ./libpng15.15.dylib
That did the trick. Now it works fine.
这就是诀窍。现在它工作正常。
