#40 Access Violation with msvc6

[Anonymous]

When I try to execute the following code with win xp,
visual c++ 6.0, log4cpp 0.3.2rc5 the I get an access
violation in ntdll.dll.

When I remove the line begins with static all works fine.
I need the static method for use of log4cpp in classes.
At the moment I retrieve an pointer to an preinitalized
Category with the Catgory::exists() method, to get
working log4cpp with classes.

Any hints? Maybe I do something wrong?
I'm new user of log4cpp.

#include <log4cpp/Category.hh>

using namespace log4cpp;

// this line produced an access violation
static Category& cat = Category::getInstance
("main.test");

int main() {

Category &log=Category::getInstance("main");
log.debug("test");
return 0;

}

[Nobody/Anonymous]

Logged In: NO

Hello,

i experienced the same problem, some other bug reports
seem to go in same direction...

Well the cause is just an old problem of dependant global
objects: construction order.

// snip begin+++ appender.cpp

namespace log4cpp {
Appender::AppenderMap* Appender::_allAppenders;
threading::Mutex Appender::_appenderMapMutex; <----
this mutex object poses the problem!!!

// snip end---

The order of initialization is undefined across compilation
units. So if someone uses (like me) static log instance
references at global files scope they must be initialized at the
beginning.

example:

static log4cpp::Category& = log4cpp::Category::getInstance
() .... constructs a new Appender, which gets added to map
of appenders.
If the mutex, which is used to protect the map is not yet
constructed (in another compilation unit) -> *boom*.

Solutions: not elegant ones yet ...

1.) instead of "threading::Mutex
Appender::_appenderMapMutex;"

use "first time access - first init"

threading::Mutex& _getAppenderMapMutex()
{
static threading::Mutex mutex;
return mutex;
}

2.) #pragma init_seg (non portable)

Regards,

Anastasius Focht

[Nobody/Anonymous]

Logged In: NO

Hello,

i experienced the same problem, some other bug reports
seem to go in same direction...

Well the cause is just an old problem of dependant global
objects: construction order.

// snip begin+++ appender.cpp

namespace log4cpp {
Appender::AppenderMap* Appender::_allAppenders;
threading::Mutex Appender::_appenderMapMutex; <----
this mutex object poses the problem!!!

// snip end---

The order of initialization is undefined across compilation
units. So if someone uses (like me) static log instance
references at global files scope they must be initialized at the
beginning.

example:

static log4cpp::Category& = log4cpp::Category::getInstance
() .... constructs a new Appender, which gets added to map
of appenders.
If the mutex, which is used to protect the map is not yet
constructed (in another compilation unit) -> *boom*.

Solutions: not elegant ones yet ...

1.) instead of "threading::Mutex
Appender::_appenderMapMutex;"

use "first time access - first init"

threading::Mutex& _getAppenderMapMutex()
{
static threading::Mutex mutex;
return mutex;
}

2.) #pragma init_seg (non portable)

Regards,

Anastasius Focht