I think you r looking for: Mapping types
The following table shows the mapping of types between Java and native code. Native Type Java Language Type Description Type signature unsigned char jboolean unsigned 8 bits Z signed char jbyte signed 8 bits B unsigned short jchar unsigned 16 bits C short jshort signed 16 bits S long jint signed 32 bits I long long __int64 jlong signed 64 bits J float jfloat 32 bits F double jdouble 64 bits D In addition, the signature "L fully-qualified-class ;" would mean the class uniquely specified by that name; e.g., the signature "Ljava/lang/String;" refers to the class java.lang.String. Also, prefixing [ to the signature makes the array of that type; for example, [I means the int array type. Here, these types are interchangeable. You can use jint where you normally use an int, and vice-versa, without any typecasting<http://en.wikipedia.org/wiki/Typecast>required. However, mapping between Java Strings and arrays to native strings and arrays is different. If you use a jstring in where a char * would be, your code could crash the JVM. Cheers... BR, Chand On Tue, Dec 1, 2009 at 2:14 AM, fadden <[email protected]> wrote: > On Nov 30, 9:08 am, bacchus <[email protected]> wrote: > > I'm looking for specific information about Android JNI Call Bridge. > > The one that exists does not suffices my needs. > > The "JNI call bridge" is a bit of code that converts an array of 32- > bit values into C-style arguments. It takes into account host- > specific calling conventions, notably which arguments go into which > registers (by type or position), which go onto the stack, and how > values should be padded. > > The sources include a version based on libffi (slow) and a few CPU- > specific implementations (ARM EABI, SH4, x86). > > > I would like to understand the mappings performed between C/C++ data > > types and Java data types. > > > > As an example, I would like to understand where and how the VMRuntime > > object is defined and mapped. > > This is beyond the scope of the JNI function call interface. If you > want higher-level object to interact more directly, you may need to > look into Cygnus CNI (requires compiler support) or JNA (convenience, > but at a price). > > Was there something specific about VMRuntime that interested you? > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected]<android-developers%[email protected]> > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
