diff options
Diffstat (limited to 'gcc/java/gcj.texi')
| -rw-r--r-- | gcc/java/gcj.texi | 39 |
1 files changed, 29 insertions, 10 deletions
diff --git a/gcc/java/gcj.texi b/gcc/java/gcj.texi index b71568a..e5b37a0 100644 --- a/gcc/java/gcj.texi +++ b/gcc/java/gcj.texi @@ -1171,9 +1171,7 @@ macros start with the @code{Jv} prefix, for example the function @code{JvNewObjectArray}. This convention is used to avoid conflicts with other libraries. Internal functions in CNI start with the prefix @code{_Jv_}. You should not call these; if you find a need to, let us -know and we will try to come up with an alternate solution. (This -manual lists @code{_Jv_AllocBytes} as an example; CNI should instead -provide a @code{JvAllocBytes} function.) +know and we will try to come up with an alternate solution. @subsection Limitations @@ -1488,11 +1486,6 @@ using standard C++ overload resolution rules. java::util::Hashtable *ht = new java::util::Hashtable(120); @end example -@deftypefun void* _Jv_AllocBytes (jsize @var{size}) -Allocates @var{size} bytes from the heap. The memory is not scanned -by the garbage collector but it freed if no references to it are discovered. -@end deftypefun - @node Arrays @section Arrays @@ -1784,11 +1777,13 @@ jint @} @end example -But this restriction can cause a problem so @acronym{CNI} includes the +@subsection RawData + +The above restriction can be problematic, so @acronym{CNI} includes the @code{gnu.gcj.RawData} class. The @code{RawData} class is a @dfn{non-scanned reference} type. In other words variables declared of type @code{RawData} can contain any data and are not checked by the -compiler in any way. +compiler or memory manager in any way. This means that you can put C/C++ data structures (including classes) in your @acronym{CNI} classes, as long as you use the appropriate cast. @@ -1826,6 +1821,30 @@ void @end example +@subsection RawDataManaged + +@code{gnu.gcj.RawDataManaged} is another type used to indicate special data used +by native code. Unlike the @code{RawData} type, fields declared as +@code{RawDataManaged} will be "marked" by the memory manager and +considered for garbage collection. + +Native data which is allocated using CNI's @code{JvAllocBytes()} +function and stored in a @code{RawDataManaged} will be automatically +freed when the Java object it is associated with becomes unreachable. + +@subsection Native memory allocation + +@deftypefun void* JvAllocBytes (jsize @var{size}) +Allocates @var{size} bytes from the heap. The memory returned is zeroed. +This memory is not scanned for pointers by the garbage collector, but will +be freed if no references to it are discovered. + +This function can be useful if you need to associate some native data with a +Java object. Using a CNI's special @code{RawDataManaged} type, native data +allocated with @code{JvAllocBytes} will be automatically freed when the Java +object itself becomes unreachable. +@end deftypefun + @node Exception Handling @section Exception Handling |