Re: Compiler bug? Two variables of same name in one scope

Jonathan Leffler <>
Tue, 30 Oct 2007 13:47:43 CST
Rune Allnor wrote:

[...] It turned out that I had renamed a
variable to a name that was already in use in the relevant

Strictly, no - the inner declaration is in a new scope.

Basically, the situation was as in this function:

double f(double a)
       double a = a; // <------------- This actually compiles...
   return a;

The variable name was already used in the argument to
the function, and I had inadvertedly used the same name
for a variable inside an if-block. As in the example above,
I used the parameter version of the variable to initialize
the local version.

What surprised me after I found the cause of the bug
was that the compiler actually accepted that piece
of code without complaints. Is that a bug in my compiler
or is the above legal C++ code?

Perfectly legal in both C++ and C.

What wouldn't work is:

int f(int i)
    int i = i;

Jonathan Leffler #include <disclaimer.h>
Guardian of DBD::Informix v2007.0914 -- tiger2 2007-10-30 12:00:04

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