libpng |重复的建筑符号

Question

我正在尝试使用Mac OS X Yosemite上的libpng编译项目。

我收到了错误：

Undefined symbols for architecture x86_64:
  "_png_create_info_struct", referenced from:
      _writePNG in qrenc.o
  "_png_create_write_struct", referenced from:
      _writePNG in qrenc.o
  "_png_destroy_write_struct", referenced from:
      _writePNG in qrenc.o
  "_png_init_io", referenced from:
      _writePNG in qrenc.o
  "_png_set_IHDR", referenced from:
      _writePNG in qrenc.o
  "_png_set_PLTE", referenced from:
      _writePNG in qrenc.o
  "_png_set_longjmp_fn", referenced from:
      _writePNG in qrenc.o
  "_png_set_pHYs", referenced from:
      _writePNG in qrenc.o
  "_png_set_tRNS", referenced from:
      _writePNG in qrenc.o
  "_png_write_end", referenced from:
      _writePNG in qrenc.o
  "_png_write_info", referenced from:
      _writePNG in qrenc.o
  "_png_write_row", referenced from:
      _writePNG in qrenc.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

所以我在我的ld电话中添加了-lpng。 现在它抛出

duplicate symbol _main in:
    .obj/main.o
    .obj/qrenc.o
ld: 1 duplicate symbol for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

链接到自制软件安装的libpng时出现相同的错误。

我做错了什么？

Answer 1

你有两个带main函数的文件（可能是main.c和qrenc.c）。从任何这些文件中删除该函数并使用-lpng。