为什么 matlab 不链接我的 C MEX 代码？
我在使用 MS VC++ 编译器编译 mex C 函数时遇到以下问题：我在一个单独的文件 disc_rhs.c 中有一个函数 disc_rhs__ ，该文件是由 f2c 创建的（应该不重要，但是......）。在我的主函数中，我在某个地方编写了
...
disc_rhs__(...);
...
尝试使用
mex sfun_kalman.cpp -L. -llapack -lcblas_WIN -lblas_WIN -lf2c disc_rhs.c kalmanfilter_f2c.cpp
这会导致错误的编译。链接器找不到 ""int __cdecl Disc_rhs__(double *,double *,double *,double *,double *)" (?disc_rhs__@@YAHPAN0000@Z)" 在 <代码>kalmanfilter.cpp。
为了编译所有内容，我将 disc_rhs.cpp 复制到 disc_rhs.h 并删除了函数声明，只留下了一个存根。我将其包含在 kalmanfilter.h 中。
那么为什么 matlab mex 编译器无法识别正确的符号并链接到 disc_rhs.c 的编译呢？
谢谢 基督教
I have the following problem in compiling my mex C functions using MS VC++ Compiler: I have a function disc_rhs__ in a separate file disc_rhs.c which was createtd by f2c (which should be unimportant, but...). In my main function I write somewhere
...
disc_rhs__(...);
...
I try to compile using
mex sfun_kalman.cpp -L. -llapack -lcblas_WIN -lblas_WIN -lf2c disc_rhs.c kalmanfilter_f2c.cpp
This leads to an error. The linker cannot find the external symbol ""int __cdecl disc_rhs__(double *,double *,double *,double *,double *)" (?disc_rhs__@@YAHPAN0000@Z)" used in the kalmanfilter.cpp.
To get everything compiling I copied the disc_rhs.cppto disc_rhs.h and removed the function declaration just letting a stub. This I included in kalmanfilter.h.
So why does matlab mex compiler not recognize the corrct symbol and link with the compilation of disc_rhs.c?
Thanks
Christian
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不要将
disc_rhs.cpp的全部内容放入头文件中，然后将其包含在另一个文件中。仅当该文件被单个源文件包含时，这才有效，一旦将其包含在另一个源文件中，您就会收到多个定义错误。解决此问题的正确方法是创建一个
disc_rhs.h文件，其中包含disc_rhs.cpp中需要由其他模块使用的所有函数的原型。然后，您可以将头文件包含在kalmanfilter.cpp中（以及需要使用这些函数的任何其他文件）。编辑：
发生错误的原因是
disc_rhs文件具有 .c 扩展名，导致 MSVC 将其编译为 C 文件。然而，由于它在 kalmanfilter.cpp 中使用，链接器期望找到一个名称已损坏的 C++ 函数，而该函数并不存在。要解决此问题，您需要告诉编译器disc_rhs__()是一个 C 函数。在disc_rhs.h中，
extern "C"指令需要出现在disc_rhs.c导出的每个项目的前面，因此，如果您有几项需要extern，则以下内容语法更方便。Do not put the entire contents of
disc_rhs.cppinto a header file and then include it in another file. This will only work as long that file is being included by a single source file, as soon as you include it in another source file you'll get multiple definition errors.The right way to fix this problem is to create a
disc_rhs.hfile that contains the prototypes of all functions fromdisc_rhs.cppthat need to be used by other modules. Then you'd include the header file inkalmanfilter.cpp(and any other files that need to use those functions).EDIT:
The error is happening because the
disc_rhsfile has a .c extension which causes MSVC to compile it as a C file. However, since it is being used inkalmanfilter.cppthe linker is expecting to find a C++ function that has been name mangled, which doesn't exist. To fix the problem, you need to tell the compiler thatdisc_rhs__()is a C function.In disc_rhs.h
The
extern "C"directive needs to appear in front of each item being exported bydisc_rhs.c, so if you have several things to extern, the following syntax is more convenient.