Here's the code:
typedef char FlagType;
int main()
{
}
int myproc( int )
{
int FlagType;
}
copied from https://docs.microsoft.com/en-us/cpp/c-language/typedef-declarations?view=msvc-160
In my understanding, 'typedef char FlagType' makes 'char a' and 'FlagType a' no difference. But I can't understand the 'int FlagType'.
The code demonstrates a pathological example. Not a standard or recommended use case.
It is shown to explain what happens when a local variable has the same name as a typedef name.
Typedef names share the name space with ordinary identifiers (see Name Spaces for more information). Therefore, a program can have a typedef name and a local-scope identifier by the same name.
If you read a few lines above, they're describing how the namespaces are separated.
This example shows a typedef of type char named FlagType and a variable in myproc() of type int named FlagType.
This is stupid, and nobody should do it, but it is legal from a language parsing standpoint.
I had the same "WTF‽" reaction when I first learned of nested anonymous structures.