JNI Header Wrapper a lightweight alternative to JNA or JNR and a helper to resolve a native lib by name and libtool version.
Unlike JNR or JNA
- all macro constants are natively resolved.
- all structures will be natively allocated and its filed natively accessed. StructTermios in Termios.java and the jni bindings Termios_Termios.c and TermiosDefines.c and TermiosFunctions.c . Struct termios varies over the OS and even on Linux on different architectures like (i.e. mips is different from the rest).
- different sizes, alignments and offset of struct members are handled natively like stuct mcontext_t Tests testAlignOfMcontext_t testSizeOfMcontext_t in SignalTest.java. Examples for struct and union and function pointer are in teh exaples modules.
- it does not use sun.misc.Unsafe but allocate the memory by itself.
- callbacks from and calls of native functions are supported Callback_I_V_Impl.java, and its counterpart CallNative_J_V.java, and their common ancestor FunctionPtr_I_V.java.
A running "real life" comparison can be found here: JNHW-Example: Compare JNHW, JNR, JNA.
Add this dependency for POSIX.
<dependency>
<groupId>de.ibapl.jnhw</groupId>
<artifactId>de.ibapl.jnhw.posix</artifactId>
<version>[3.0.0,4.0.0)</version>
</dependency>
and this for the Windows API
<dependency>
<groupId>de.ibapl.jnhw</groupId>
<artifactId>de.ibapl.jnhw.winapi</artifactId>
<version>[3.0.0,4.0.0)</version>
</dependency>
If an native error occured and the called function flags an error condition to the caller. One calls for ISO C errno and for the windows API GetLastError(). this is done in the jni wrapper which throws the checked exception NativeErrorException in that case.
| Test Platform | VM version | Hotspot VM (Java Foreign) | Zero VM (Java Foreign) | Hotspot VM (JNI) | Zero VM (JNI) |
|---|---|---|---|---|---|
| aarch64-linux-gnu | 19.0.1 | success 2023-01-26 | success 2023-01-27 | success 2023-01-27 | crashed 2023-01-27 |
| arm-linux-gnueabihf | 19.0.1 | n.a. 2023-01-26 | n.a. 2023-01-26 | success 2023-01-26 | success 2023-01-26 |
| i386-linux-gnu | 19.0.1 | n.a. 2023-01-26 | n.a. 2023-01-26 | success 2023-01-26 | success 2023-01-26 |
| mipsel-linux-gnu | 19.0.1 | n.a. 2023-01-26 | n.a. 2023-01-26 | n.a. 2023-01-26 | success 2023-01-26 |
| mips64el-linux-gnu | 19.0.1 | n.a. 2023-01-27 | n.a. 2023-01-27 | n.a. 2023-01-27 | |
| powerpc-linux-gnu | 19.0.1 | n.a. 2023-01-26 | n.a. 2023-01-26 | n.a. 2023-01-26 | crashed 2023-01-26 |
| powerpc64le-linux-gnu | 19.0.1 | n.a. 2023-01-26 | n.a. 2023-01-26 | success 2023-01-26 | success 2023-01-26 |
| riscv64-linux-gnu | 19.0.1 | n.a. 2023-01-26 | n.a. 2023-01-26 | success 2023-01-26 | success 2023-01-26 |
| s390x-linux-gnu | 19.0.1 | n.a. 2023-01-26 | n.a. 2023-01-26 | success 2023-01-26 | success 2023-01-26 |
| x86_64-apple-darwin | 19.0.1 | success 2023-01-27 | n.a. 2023-01-27 | success 2023-01-26 | n.a. 2023-01-27 |
| x86_64-freebsd-bsd | 19.0.1 | success 2023-01-27 | n.a. 2023-01-26 | success 2023-01-27 | n.a. 2023-01-26 |
| x86_64-openbsd-bsd | 19.0.1 | no OpenJDK19 2023-01-27 | no OpenJDK19 2023-01-27 | no OpenJDK19 2023-01-27 | no OpenJDK19 2023-01-27 |
| x86_64-linux-gnu | 19.0.1 | success 2023-01-26 | crashed 2023-01-26 | success 2023-01-26 | success 2023-01-26 |
| x86_64-windows-pe32+ | 19.0.1 | success 2023-01-26 | n.a. 2023-01-27 | success 2023-01-27 | zero n.a. 2023-01-27 |
n.a. ... the VM and/or feature are not available.
See subdirectory it/hello-world/.
run mvn exec:java -Dexec.mainClass="de.ibapl.jnhw.it.hello_world.App" in it/hello_world.
Import Unistd in a static manner so the code may become less noisy.
package de.ibapl.jnhw.it.hello_world;
import de.ibapl.jnhw.NativeErrorException;
//Import only the needed define from the wrapper of posix's unistd.h.h
import static de.ibapl.jnhw.posix.Unistd.STDOUT_FILENO;
//Import only the needed method from the wrapper of iso c's unistd.h.h
import static de.ibapl.jnhw.posix.Unistd.write;
public class Posix {
public static void sayHello() throws NativeErrorException {
int bytesWritten = write(STDOUT_FILENO, "Hello World! from POSIX\n".getBytes());
System.out.println("Bytes written: " + bytesWritten);
}
}package de.ibapl.jnhw.it.hello_world;
import de.ibapl.jnhw.NativeErrorException;
//Import only the needed define from the wrapper of processenv.h
import static de.ibapl.jnhw.winapi.Winbase.STD_OUTPUT_HANDLE;
//Import only the needed method from the wrapper of processenv.h
import static de.ibapl.jnhw.winapi.ProcessEnv.GetStdHandle;
//Import only the needed method from the wrapper of fileapi.h
import static de.ibapl.jnhw.winapi.Fileapi.WriteFile;
public class Windows {
public static void sayHello() throws NativeErrorException {
int bytesWritten = WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), "Hello World! from WIN API\n".getBytes());
System.out.println("Bytes written: " + bytesWritten);
}
}create a file named test.c and include the needed headers. run
gcc -dD -dI -E test.c | lessto see the preprocessed defines