Does Not Name A Type in C++
in C++ when i get an error that says xxxxx does not name a type in yyy.h
What does that mean?
yyy.h
has included the header that xxxx
is in.
Example, I use:
typedef CP_M_ReferenceCounted FxRC;
and I have included CP_M_ReferenceCounted.h
in yyy.h
I am missing开发者_高级运维 some basic understanding, what is it?
That seems you need to refer to the namespace accordingly. For example, the following yyy.h and test.cpp have the same problem as yours:
//yyy.h
#ifndef YYY_H__
#define YYY_H__
namespace Yyy {
class CP_M_ReferenceCounted
{
};
}
#endif
//test.cpp
#include "yyy.h"
typedef CP_M_ReferenceCounted FxRC;
int main(int argc, char **argv)
{
return 0;
}
The error would be
...error: CP_M_ReferenceCounted does not name a type
But add a line "using namespace Yyy;" fixes the problem as below:
//test.cpp
#include "yyy.h"
// add this line
using namespace Yyy;
typedef CP_M_ReferenceCounted FxRC;
...
So please check the namespace scope in your .h headers.
The inclusion of the CP_M_ReferenceCounted type is probably lexically AFTER the typedef... can you link to the two files directly, or reproduce the problem in a simple sample?
Although possibly unrelated to OP's original question... this is an error I just had and shows how this error could occur.
When you define a type in a C++ class and you return it, you need to specify the class in which the type belongs.
For example:
class ClassName{
public:
typedef vector<int> TypeName;
TypeName GetData();
};
Then GetName() must be defined as:
ClassName::TypeName ClassName::GetData(){...}
not
TypeName ClassName::GetData(){...}
Otherwise the compiler will come back with the error:
error: 'TypeName' does not name a type
Yes, you should try to check the
namespace
first.
Be sure you didn't copy paste this yyy.h file from some other class header and keep the same "YYY_H__" in the new #ifndef as in the original file. I just did this and realized my mistake. Make sure to update your new YYY_H__ to represent the new class. Otherwise, obviously, YYY_H__ will already be defined from the original file and the important stuff in this header will be skipped.
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