C ++< complex>和< complex.h>在同一个文件

之外的上下文中使用名称 complex code>，例如 std :: complex ，然后扩展为 std :: _ Complex 因此，如果你在C ++中使用< complex> ，你应该摆脱这个宏： #include< complex.h> #undef complex 实际上，g ++从4.8开始支持 $ b $ b 请注意，启用C ++ 11时，您也不会得到错误。 I have a large code base that uses the c++ <complex> header and many std::complex<double> objects. But now I also want to use a couple other libraries (fftw and spinsfast) that use <complex.h>. Unfortunately, mixing these two types of complex seems to be incompatible with gcc 4.6.1 (presumably among others).Here's a minimal working example showing the error:// This is what I do for my various complex objects#include <complex>// This is one of many things FFTW/spinsfast essentially doextern "C" { #include <complex.h>}int main() { std::complex<double>(1.0,2.0); return 0;}And when I compile:> g++ test.cpp -o testtest.cpp: In function ‘int main()’:test.cpp:7:8: error: expected unqualified-id before ‘_Complex’test.cpp:7:8: error: expected ‘;’ before ‘_Complex’Evidently, gcc is translating std::complex<double> into _Complex, which somehow is also undefined. [This works fine on my macbook, which uses Apple LLVM version 5.1; this compiler error is happening on a cluster that I need to support.]I can't even figure out where this is coming from; none of the include files in my gcc installation have "_Complex" -- though they do have "_ComplexT". How do I debug this kind of thing?Or more helpfully, how do I solve this compiler error in a way that will work for more than just a small slice of gccs? 解决方案 In C, _Complex is a keyword used to declare complex numbers: float _Complex. However, they #define complex _Complex so you can write float complex which looks nicer.Of course, you get in trouble when using the name complex in a context other than where you want _Complex, such as std::complex, which then expands to std::_Complex.So if you use <complex> in C++, you should get rid of this macro:#include <complex.h>#undef complexThat's actually what g++ does since 4.8 to support both <complex> and <complex.h> in the same translation unit.Note that when enabling C++11, you won't get the error either. 这篇关于C ++&lt; complex&gt;和&lt; complex.h&gt;在同一个文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！