gds32.dll!ISC_get_host(char * string, unsigned short length) Line 278	C++
>	gds32.dll!make_object_name(char * buffer, unsigned int bufsize, const char * object_name, const char * object_type) Line 4322	C++
 	gds32.dll!ISC_mutex_init(mtx * mutex, const char * mutex_name) Line 3838	C++
 	gds32.dll!Jrd::LockManager::initialize(sh_mem * shmem_data, bool initializeMemory) Line 2402	C++
 	gds32.dll!Jrd::LockManager::initialize(void * arg, sh_mem * shmem, bool init) Line 476	C++
 	gds32.dll!ISC_map_file(int * status_vector, const char * filename, void (void *, sh_mem *, bool) * init_routine, void * init_arg, unsigned long length, sh_mem * shmem_data) Line 2827	C++
 	gds32.dll!Jrd::LockManager::attach_shared_file(int * status) Line 340	C++
 	gds32.dll!Jrd::LockManager::acquire_shmem(long owner_offset) Line 1155	C++
 	gds32.dll!Jrd::LockManager::create_owner(int * status_vector, unsigned __int64 owner_id, unsigned char owner_type, long * owner_handle) Line 1736	C++
 	gds32.dll!Jrd::LockManager::initializeOwner(Jrd::thread_db * tdbb, unsigned __int64 owner_id, unsigned char owner_type, long * owner_handle) Line 413	C++
 	gds32.dll!LCK_init(Jrd::thread_db * tdbb, Jrd::lck_owner_t owner_type) Line 590	C++
 	gds32.dll!jrd8_attach_database(int * user_status, const char * filename, Jrd::Attachment * * handle, short dpb_length, const unsigned char * dpb) Line 1101	C++
 	gds32.dll!isc_attach_database(int * user_status, short file_length, const char * file_name, void * * public_handle, short dpb_length, const char * dpb) Line 1494	C++

>	gds32.dll!os_utils::createLockDirectory(const char * pathname) Line 181	C++
 	gds32.dll!gds__prefix_lock(char * string, const char * root) Line 1765	C++
 	gds32.dll!ISC_map_file(int * status_vector, const char * filename, void (void *, sh_mem *, bool) * init_routine, void * init_arg, unsigned long length, sh_mem * shmem_data) Line 2819	C++
 	gds32.dll!Jrd::LockManager::attach_shared_file(int * status) Line 340	C++
 	gds32.dll!Jrd::LockManager::acquire_shmem(long owner_offset) Line 1155	C++
 	gds32.dll!Jrd::LockManager::create_owner(int * status_vector, unsigned __int64 owner_id, unsigned char owner_type, long * owner_handle) Line 1736	C++
 	gds32.dll!Jrd::LockManager::initializeOwner(Jrd::thread_db * tdbb, unsigned __int64 owner_id, unsigned char owner_type, long * owner_handle) Line 413	C++
 	gds32.dll!LCK_init(Jrd::thread_db * tdbb, Jrd::lck_owner_t owner_type) Line 590	C++
 	gds32.dll!jrd8_attach_database(int * user_status, const char * filename, Jrd::Attachment * * handle, short dpb_length, const unsigned char * dpb) Line 1101	C++
 	gds32.dll!isc_attach_database(int * user_status, short file_length, const char * file_name, void * * public_handle, short dpb_length, const char * dpb) Line 1494	C++

>	gds32.dll!ISC_map_file(int * status_vector, const char * filename, void (void *, sh_mem *, bool) * init_routine, void * init_arg, unsigned long length, sh_mem * shmem_data) Line 2819	C++
 	gds32.dll!Jrd::LockManager::attach_shared_file(int * status) Line 340	C++
 	gds32.dll!Jrd::LockManager::acquire_shmem(long owner_offset) Line 1155	C++
 	gds32.dll!Jrd::LockManager::create_owner(int * status_vector, unsigned __int64 owner_id, unsigned char owner_type, long * owner_handle) Line 1736	C++
 	gds32.dll!Jrd::LockManager::initializeOwner(Jrd::thread_db * tdbb, unsigned __int64 owner_id, unsigned char owner_type, long * owner_handle) Line 413	C++
 	gds32.dll!LCK_init(Jrd::thread_db * tdbb, Jrd::lck_owner_t owner_type) Line 590	C++
 	gds32.dll!jrd8_attach_database(int * user_status, const char * filename, Jrd::Attachment * * handle, short dpb_length, const unsigned char * dpb) Line 1101	C++
 	gds32.dll!isc_attach_database(int * user_status, short file_length, const char * file_name, void * * public_handle, short dpb_length, const char * dpb) Line 1494	C++

// src\lock\lock.cpp
	while (SRQ_EMPTY(m_header->lhb_processes))
	{
		if (!m_sharedFileCreated) // <---Вот отсюда!!!!!
		{
			ISC_STATUS_ARRAY local_status;

			// Someone is going to delete shared file? Reattach.
			if (ISC_mutex_unlock(MUTEX) != 0)
			{
				bug(NULL, "ISC_mutex_unlock failed (acquire_shmem)");
			}
			detach_shared_file(local_status);

			THD_yield();

			if (!attach_shared_file(local_status)) {
				bug(local_status, "ISC_map_file failed (reattach shared file)");
			}
			if (ISC_mutex_lock(MUTEX)) {
				bug(NULL, "ISC_mutex_lock failed (acquire_shmem)");
			}
		} // <--- И до сюда!!!!!
		else
		{
			// complete initialization
			m_sharedFileCreated = false;

			// no sense thinking about statistics now
			prior_active = 0;

			break;
		}
	}

#include <string>

#include "Poco/Process.h"
#include "Poco/Pipe.h"
#include "ibase.h"

#pragma comment(lib, "fbclient_ms.lib")

const std::string server_and_path = "test_db.fdb";
const unsigned StatusLen = 20;

Poco::Pipe in_pipe;
Poco::Pipe out_pipe;


void connect1()
{
	isc_db_handle db_handle = nullptr;
	ISC_STATUS status_vect[StatusLen] = {};
	char pdb[1] = { isc_dpb_version1 };

	// connect 
	isc_attach_database(
		status_vect,
		server_and_path.size(),
		server_and_path.c_str(),
		&db_handle,
		sizeof(pdb),
		pdb
	);

	// start process
	Poco::Process::launch("cmd.exe", {}, "", &in_pipe, &out_pipe, nullptr);

	// disconnect
	isc_detach_database(status_vect, &db_handle);
}


void connect2()
{
	isc_db_handle db_handle = nullptr;
	char pdb[1] = { isc_dpb_version1 };

	ISC_STATUS status_vect[StatusLen] = {};

	// connect
	isc_attach_database( // <- ВИСНЕТ ЗДЕСЬ!
		status_vect,
		server_and_path.size(),
		server_and_path.c_str(),
		&db_handle,
		sizeof(pdb),
		pdb
	);

	// сюда уже не доходит :-(
	isc_detach_database(status_vect, &db_handle);
}


int main(int argc, char* argv[])
{
	connect1();
	connect2();
	return 0;
}

Poco::Process::launch("calc.exe", {}, "");