From 92c76eba665f8817964a09325fb8a358d23c6221 Mon Sep 17 00:00:00 2001 From: Bryce McKinlay Date: Mon, 8 Apr 2002 06:37:26 +0000 Subject: [PATCH] * gcj.texi (Invocation): Document CNI invocation API. From-SVN: r52012 --- gcc/java/ChangeLog | 4 +++ gcc/java/gcj.texi | 64 +++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 67 insertions(+), 1 deletion(-) diff --git a/gcc/java/ChangeLog b/gcc/java/ChangeLog index ae709011528..60620e60fd2 100644 --- a/gcc/java/ChangeLog +++ b/gcc/java/ChangeLog @@ -1,3 +1,7 @@ +2002-04-08 Bryce McKinlay + + * gcj.texi (Invocation): Document CNI invocation API. + 2002-04-04 Neil Booth * expr.c (truthvalue_conversion): Rename. Update. diff --git a/gcc/java/gcj.texi b/gcc/java/gcj.texi index b6067ce545b..c7776ebfb0f 100644 --- a/gcc/java/gcj.texi +++ b/gcc/java/gcj.texi @@ -860,6 +860,7 @@ alternative to the standard JNI (Java Native Interface). * Mixing with C++:: How CNI can interoperate with C++. * Exception Handling:: How exceptions are handled. * Synchronization:: Synchronizing between Java and C++. +* Invocation:: Starting the Java runtime from C++. * Reflection:: Using reflection from C++. @end menu @@ -1544,7 +1545,7 @@ in your @acronym{CNI} classes, as long as you use the appropriate cast. class ::MyClass : public java::lang::Object @{ - GcjRaw string; + gnu.gcj.RawData string; MyClass (); gnu.gcj.RawData getText (); @@ -1683,6 +1684,67 @@ of a synchronized native method to handle the synchronization In otherwords, you need to manually add @code{JvSynchronize} in a @code{native synchornized} method. +@node Invocation +@section Invocation + +CNI permits C++ applications to make calls into Java classes, in addition to +allowing Java code to call into C++. Several functions, known as the +@dfn{invocation API}, are provided to support this. + +@deftypefun jint JvCreateJavaVM (void* @var{vm_args}) +Initializes the Java runtime. This function performs essential initialization +of the threads interface, garbage collector, exception handling and other key +aspects of the runtime. It must be called once by an application with +a non-Java @code{main()} function, before any other Java or CNI calls are made. +It is safe, but not recommended, to call @code{JvCreateJavaVM()} more than +once provided it is only called from a single thread. +The @var{vmargs} parameter can be used to specify initialization parameters +for the Java runtime. It may be @code{NULL}. +This function returns @code{0} upon success, or @code{-1} if the runtime is +already initialized. + +@emph{Note:} In GCJ 3.1, the @code{vm_args} parameter is ignored. It may be +used in a future release. +@end deftypefun + +@deftypefun java::lang::Thread* JvAttachCurrentThread (jstring @var{name}, java::lang::ThreadGroup* @var{group}) +Registers an existing thread with the Java runtime. This must be called once +by a multi-threaded C++ application for each thread, before that thread makes +any other Java or CNI calls. +@var{name} specifies a name for the thread. It may be @code{NULL}, in which +case a name will be generated. +@var{group} is the ThreadGroup in which this thread will be a member. If it +is @code{NULL}, the thread will be a member of the main thread group. +The return value is the Java @code{Thread} object that represents the thread. +@end deftypefun + +@deftypefun jint JvDetachCurrentThread () +Unregisters a thread from the Java runtime. This should be called by threads +that were attached using @code{JvAttachCurrentThread()}, after they have +finished making calls to Java code. This ensures that any resources associated +with the thread become eligible for garbage collection. +This function returns @code{0} upon success. +@end deftypefun + +The following example demonstrates the use of @code{JvCreateJavaVM()} from +a simple C++ application. It can be compiled with +@command{c++ test.cc -lgcj}. + +@example +// test.cc +#include +#include +#include + +int main(int argc, char *argv) +@{ + using namespace java::lang; + + JvCreateJavaVM(NULL); + String *hello = JvNewStringLatin1("Hello from C++"); + System::out->println(hello); +@} +@end example @node Reflection @section Reflection -- 2.30.2