GThreads.h File Reference

#include "DjVuGlobal.h"
#include "GException.h"

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Classes
class	GCriticalSection
class	GCriticalSectionLock
class	GEvent
class	GMonitor
	Monitor class. More...
class	GMonitorLock
	Wrapper for mutually exclusive code. More...
class	GSafeFlags
	A thread safe class representing a set of flags. More...
class	GThread
	Thread class. More...
Defines
GThreads.h
Files #"GThreads.h"# and #"GThreads.cpp"# implement common entry points for multithreading on multiple platforms. Each execution thread is represented by an instance of class {GThread}. Synchronization is provided by class {GMonitor} which implements a monitor (C.A.R Hoare, Communications of the ACM, 17(10), 1974). The value of compiler symbol THREADMODEL# selects an appropriate implementation for these classes. The current implementation supports the following values: {description} [-DTHREADMODEL=NOTHREADS] Dummy implementation. This is a good choice when the multithreading features are not required, because it minimizes the portability problems. This is currently the default when compiling under Unix. [-DTHREADMODEL=WINTHREADS] Windows implementation. This is the default when compiling under Windows. [-DTHREADMODEL=MACTHREADS] Macintosh implementation, which is based on the MacOS cooperative model. The current implementation does not yet fully support synchronization. This is the default when compiling under MacOS. [-DTHREADMODEL=POSIXTHREADS] Posix implementation. This implementation also supports DCE threads. The behavior of the code is subject to the quality of the system implementation of Posix threads. [-DTHREADMODEL=COTHREADS] Custom cooperative threads. These custom threads do not redefine system calls. Before executing a potentially blocking system function, each thread must explicitly check whether it is going to block and yield control explicitly if this is the case. This code must be compiled with a patched version of egcs-1.1.1 {http://egcs.cygnus.com}. The patch addresses exception thread-safety and is provided in #"@Tools/libgcc2.c.diff"#. Once you get the right compiler, this implementation is remarkably compact and portable. A variety of processors are supported, including mips, intel, sparc, hppa, and alpha. [-DTHREADMODEL=JRITHREADS] Java implementation hooks. Multi-threading within a Netscape plugin can be tricky. A simple idea however consists of implementing the threading primitives in Java and to access them using JRI. The classes just contain a JRIGlobalRef. This is not a real implementation since everything (Java code, native functions, stubs, exception thread safety) must be addressed by the plugin source code. Performance may be a serious issue. {description} { Portability}: The simultaneous use of threads and exceptions caused a lot of portability headaches under Unix. We eventually decided to implement the COTHREADS cooperative threads (because preemptive threads have more problems) and to patch EGCS in order to make exception handling COTHREAD-safe. Portable threads Author: L\'eon Bottou <leonb@research.att.com> -- initial implementation.\ Praveen Guduru <praveen@sanskrit.lz.att.com> -- mac implementation. From: Leon Bottou, 1/31/2002 Almost unchanged by Lizardtech. GSafeFlags should go because it not as safe as it claims. Version: $Id: GThreads.h,v 1.10 2003/11/07 22:08:21 leonb Exp $#
#define	COTHREADS   1
#define	JRITHREADS   2
#define	MACTHREADS   12
#define	NOTHREADS   0
#define	POSIXTHREADS   10
#define	THREADMODEL   NOTHREADS
#define	WINTHREADS   11

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Define Documentation

#define COTHREADS   1

Definition at line 138 of file GThreads.h.

#define JRITHREADS   2

Definition at line 139 of file GThreads.h.

#define MACTHREADS   12

Definition at line 142 of file GThreads.h.

#define NOTHREADS   0

Definition at line 137 of file GThreads.h.

#define POSIXTHREADS   10

Definition at line 140 of file GThreads.h.

#define THREADMODEL   NOTHREADS

Definition at line 157 of file GThreads.h.

#define WINTHREADS   11

Definition at line 141 of file GThreads.h.