Calling copyObject in C++ without GNU extensions (e.g. when using
-std=c++11 instead of -std=gnu++11) fails with an error like this:
error: use of undeclared identifier 'typeof'; did you mean 'typeid'
This is due to the C compiler used to compile PostgreSQL supporting
typeof, but that function actually not being present in the C++
compiler. This fixes that by explicitely checking for typeof support
in C++, and then either use that or define typeof ourselves as:
std::remove_reference_t<decltype(x)>
According to the paper that led to adding typeof to the C standard,
that's the C++ equivalent of the C typeof:
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2927.htm#existing-decltype
Author: Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://www.postgresql.org/message-id/flat/DGPW5WCFY7WY.1IHCDNIVVT300%2540jeltef.nl
Most of the StaticAssert macros already worked in C++ with Clang and
GCC:(the only compilers we're currently testing C++ extension support
for). This adds a regression test for them in our test C++ extension,
so we can safely change their implementation without accidentally
breaking C++.
The only macros that StaticAssert macros that don't work yet are the
StaticAssertVariableIsOfType and StaticAssertVariableIsOfTypeMacro.
These will be added in a follow-on commit.
Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://www.postgresql.org/message-id/flat/CAGECzQR21OnnKiZO_1rLWO0-16kg1JBxnVq-wymYW0-_1cUNtg@mail.gmail.com
All of these macros already work in C++ with Clang and GCC (the only
compilers we're currently testing C++ extension support for). This
adds a regression test for them in our test C++ extension, so we can
safely change their implementation without accidentally breaking C++.
Some of the List macros didn't work in C++ in the past (see commit
d5ca15ee5), and this would have caught that.
Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://www.postgresql.org/message-id/flat/CAGECzQR21OnnKiZO_1rLWO0-16kg1JBxnVq-wymYW0-_1cUNtg@mail.gmail.com
While we already test that our headers are valid C++ using
headerscheck, it turns out that the macros we define might still
expand to invalid C++ code. This adds a minimal test extension that
is compiled using C++ to test that it's actually possible to build and
run extensions written in C++. Future commits will improve C++
compatibility of some of our macros and add usage of them to this
extension make sure that they don't regress in the future.
The test module is for the moment disabled when using MSVC. In
particular, the use of designated initializers in PG_MODULE_MAGIC
would require C++20, for which we are currently not set up. (GCC and
Clang support it as extensions.) It is planned to fix this.
Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://www.postgresql.org/message-id/flat/CAGECzQR21OnnKiZO_1rLWO0-16kg1JBxnVq-wymYW0-_1cUNtg@mail.gmail.com
