Here is a list of all files with brief descriptions:

appender.h
appenderattachable.h
appenderattachableimpl.h
asyncappender.h
callbackappender.h
clfsappender.h
clogger.h	Module: Log4CPLUS File: clogger.h Created: 01/2011 Author: Jens Rehsack
config.hxx
configurator.h
connectorthread.h
consoleappender.h
customloglevelmanager.h	This header contains declaration internal to log4cplus
cygwin-win32.h
deviceappender.hxx
env.h
exception.h
factory.h
fileappender.h
fileinfo.h
filter.h	This header defines Filter and all of it's subclasses
fstreams.h
hierarchy.h
hierarchylocker.h
initializer.h
internal.h	This header contains declaration internal to log4cplus
layout.h
lockfile.h
log4cplus.h
log4judpappender.h
logger.h	This header defines the Logger class and the logging macros
loggerfactory.h
loggerimpl.h
loggingevent.h
loggingmacros.h	This header defines the logging macros
loglevel.h	This header defines the LogLevel type
loglog.h
macosx.h
mdc.h
msttsappender.h
ndc.h	This header defined the NDC class
nteventlogappender.h
nullappender.h
objectregistry.h
pointer.h
property.h
qt4debugappender.h
qt5debugappender.h
queue.h
rootlogger.h
snprintf.h
helpers/socket.h
internal/socket.h	This header contains declaration internal to log4cplus
socketappender.h
socketbuffer.h
streams.h
stringhelper.h
syncprims-cxx11.h	This file contains implementations of synchronization primitives using the C++11 API
syncprims-impl.h
syncprims-pmsm.h	This file contains implementations of reader-writer locking primitive using other primitives, IOW poor man's rwlock
syncprims-pub-impl.h
syncprims.h
syslogappender.h
tchar.h
thread-config.h
threads-impl.h
threads.h
timehelper.h
tls.h
tracelogger.h
tstring.h
version.h
win32.h
win32consoleappender.h
win32debugappender.h
windowsh-inc-full.h
windowsh-inc.h