Question

我想用c ++编辑一些jpeg文件。我链接到libjpg并编译了我的代码。编译器抱怨typedef FILE和size_t。我搜索了这个问题，发现这个库是为了在C而不是C ++下编译的，所以我们必须手动将include stdio.h添加到“jpeglib.h”。我做到了，但这次编译器给了我以下错误：

undefined reference to `jpeg_CreateCompress'    JPGImage.cpp    /KFCK/src   line 47 C/C++ Problem
undefined reference to `jpeg_CreateDecompress'  JPGImage.cpp    /KFCK/src   line 92 C/C++ Problem
undefined reference to `jpeg_destroy_compress'  JPGImage.cpp    /KFCK/src   line 77 C/C++ Problem
undefined reference to `jpeg_destroy_decompress'    JPGImage.cpp    /KFCK/src   line 123    C/C++ Problem
undefined reference to `jpeg_finish_compress'   JPGImage.cpp    /KFCK/src   line 74 C/C++ Problem
undefined reference to `jpeg_finish_decompress' JPGImage.cpp    /KFCK/src   line 120    C/C++ Problem
undefined reference to `jpeg_read_header'   JPGImage.cpp    /KFCK/src   line 102    C/C++ Problem
undefined reference to `jpeg_read_scanlines'    JPGImage.cpp    /KFCK/src   line 115    C/C++ Problem
undefined reference to `jpeg_set_defaults'  JPGImage.cpp    /KFCK/src   line 61 C/C++ Problem
undefined reference to `jpeg_set_quality'   JPGImage.cpp    /KFCK/src   line 62 C/C++ Problem
undefined reference to `jpeg_start_compress'    JPGImage.cpp    /KFCK/src   line 65 C/C++ Problem
undefined reference to `jpeg_start_decompress'  JPGImage.cpp    /KFCK/src   line 104    C/C++ Problem

找不到库函数。如果我删除stdio.h行并再次编译，我得到这个：

‘FILE’ has not been declared    KFCK        line 956, external location: /home/../jpeg-8c/jpeglib.h C/C++ Problem
‘FILE’ has not been declared    KFCK        line 957, external location: /home/../jpeg-8c/jpeglib.h C/C++ Problem
‘size_t’ does not name a type   KFCK        line 756, external location: /home/../jpeg-8c/jpeglib.h C/C++ Problem
‘size_t’ does not name a type   KFCK        line 768, external location: /home/../jpeg-8c/jpeglib.h C/C++ Problem
‘size_t’ has not been declared  KFCK        line 799, external location: /home/../jpeg-

我应该做什么？

Answer 1

把#include放回去。但它看起来非常像你在链接时没有添加-ljpeg或类似的东西。此外，您需要确保如果您在C ++代码中包含此内容，则可能需要执行以下操作：

extern "C" {
#include <jpeglib.h>
}

如何在jpeglib.h中包含<stdio.h>（jpeg-8c）</stdio.h>

1 个答案: