Copying a string into an array of char in managed code

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Copying a string into an array of char in managed code

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Question:

I've got an array of char in a managed class as declared below and need to initialize it with strcpy(). (I'm porting old code.) I get the following error message:
error C2664: 'strcpy' : cannot convert parameter 1 from 'char [255]' to 'char *'

Answer:

The array data is physically part of a __gc object, and thus the corresponding pointer type is an interior __gc pointer. To pass it to strcpy, you'll have to convert it to a pinning pointer using the __pin keyword - as shown in the code below.

You can reuse that pinning pointer for other arrays of char without casing a memory leak. In addition, you can unpin an object by assigning NULL to the pinning pointer.

public __gc class CMyClass{ 
public:
   data char[255];
}


// ..

CMyClass::CMyClass() {

  // this will not work
  strcpy(data, "Start");

  // the following will work
  char __pin * p;
  p = data; strcpy(p, "Start");

  // ..
}

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