1/5/2023 0 Comments Ultraviewer manipulatepacket error : 1 :object variable or with block variable not set![]() That's the difference between regular external variables and constant. Here, we should use the extern keyword to declare the constant in all files that use the constant. However, if we want to make a constant have external linkage, we can use the extern keyword to override the default internal linkage: Note that only the declarations without the extern can initialize values. In other words, only one file can contain the preceding declaration, and the other files have to provide reference declarations using the extern keyword. However, if global const had external linkage as regular variables do, the const declaration would be an error because we can define a global variable in one file only. So, the "const int a = 10" becomes "static const int a = 10". In other words, C++ treats a global const definition as if the static had been used as in the following code. While a global variable has external linkage by default, a const global has internal linkage by default. ![]() The const in C++ has gives a little bit of twist to the default storage classes. Int zz = 10 * x // not allowed, x is not constant ![]()
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