[util.cpp#L216](https://github.com/bitcoin/bitcoin/blob/master/src/util.cpp#L216) 
if `fopen `failed, a null file pointer could be passed to `FileWriteStr(vMsgsBeforeOpenLog->front(), fileout);`
#include <boost/filesystem/fstream.hpp>
#include <boost/foreach.hpp>
#include <boost/program_options/detail/config_file.hpp>
#include <boost/program_options/parsers.hpp>
#include <boost/thread.hpp>
#include <openssl/crypto.h>
#include <openssl/rand.h>
#include <openssl/conf.h>
namespace boost {
    namespace program_options {
        std::string to_internal(const std::string&);
    }
} 
using namespace std;
const char * const BITCOIN_CONF_FILENAME = "bitcoin.conf";
const char * const BITCOIN_PID_FILENAME = "bitcoind.pid";
CCriticalSection cs_args;
map<string, string> mapArgs;
static map<string, vector<string> > _mapMultiArgs;
const map<string, vector<string> >& mapMultiArgs = _mapMultiArgs;
bool fDebug = false;
bool fPrintToConsole = false;
bool fPrintToDebugLog = true;
bool fLogTimestamps = DEFAULT_LOGTIMESTAMPS;
bool fLogTimeMicros = DEFAULT_LOGTIMEMICROS;
bool fLogIPs = DEFAULT_LOGIPS;
std::atomic<bool> fReopenDebugLog(false);
CTranslationInterface translationInterface;
static CCriticalSection** ppmutexOpenSSL;
void locking_callback(int mode, int i, const char* file, int line) NO_THREAD_SAFETY_ANALYSIS