https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94764
Bug ID: 94764
Summary: block extern incorrectly resolved to external linkage
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: tabloid.adroit at gmail dot com
Target Milestone: ---
Related to DR426
source:
https://stackoverflow.com/questions/61276220/why-same-named-extern-local-variables-in-different-blocks-get-different-linkages
// foo.cpp
int var = 10; // external linkage
// main.cpp
#include <iostream>
static int var = 100; // internal linkage
int main() {
extern int var; // internal linkage
std::cout << var << std::endl;
{
extern int var; // g++: external linkage , clang++: internal
linkage
std::cout << var << std::endl;
{
extern int var; // g++: external linkage , clang++: internal
linkage
std::cout << var << std::endl;
}
}
}
g++ : "100 10 10"
clang++ : "100 100 100" (msvc++)
[basic.link] #6 is pretty clear about this. I'm not sure it is a UB.
