[libpq] Segmentation fault when call PQfinish inside singletone pattern

I'm create singletone class, and want to add inside PGconn object.

This class, in the past, will provide connections to DB.

// postgresql#include
<libpq-fe.h>//==============================================================================class
TestST{public:
static TestST& getInstance()
{
static TestST test;
return test;
}
bool createConnection()
{
mConn.reset( PQsetdbLogin("localhost", "5432", NULL, NULL,
"test_db", "user_app",
"passwd"),
&PQfinish); // [SIGSEGV when delete] passing a
reference to the destroy function
return true;
}
private:
TestST()
{

}private:
std::shared_ptr<PGconn> mConn; // smart pointer to postgres connetion object};
//==============================================================================int
main(int argc, char** argv){
TestST::getInstance().createConnection(); // create singletone and connection

return 0;}//==============================================================================

When singletone is deleted, function PQfinish calls signal Segmentation
fault.

But If I move the initialization of mConn to the constructor - it's work.
If I build and run on windows (MSVC) - it's work.

postgres version 9.6.9; OS - Debian 9; gcc version 6.3.0

Faithfully yours Ilya Galdin