https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83749
Bug ID: 83749
Summary: Types with different language linkage are treated as
equivalent types
Product: gcc
Version: 7.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dan.cer...@cgc-instruments.com
Target Milestone: ---
g++ has an inaccuracy when following the C++03 standard concerning the equality
of types with different linkage. Section 7.5.1 states that: "Two function types
with different language linkages are distinct types even if they are otherwise
identical.".
Then the following code snippet should not compile:
~~~~~~~~~~~~~~~~~~~~~~~~{.cpp}
extern "C" void (*const interruptVectors[])();
typedef void (*ISR_t)(void);
static ISR_t* source_vector_table = const_cast<ISR_t*>(interruptVectors);
~~~~~~~~~~~~~~~~~~~~~~~~
Although interruptVectors is of type const ISR_t* it has C linkage, thus the
types should be different and the const_cast should not work.
I have discovered this behavior when compiling a code base with TI's ARM
compiler which choked on the aforementioned snippet. A TI employee then
referred me to the C++03 standard
(https://e2e.ti.com/support/development_tools/compiler/f/343/t/654558), which
seems to back the compiler's behavior.
