Reply to thread

Message: [QUOTE="david.brown.0, post: 2544428"] I'm trying to make a Java program access a parallel port. Java's comm API does not provide me with the control I need. I need to be able to write to the data and control pins and read the status pins. Any Java people know a good solution? I'm trying to use JNI and create my own library, but building the library gives me these errors: ld: warning: cannot find entry symbol _start; defaulting to 0000000008048094 ParallelPort.o: In function `Java_ParallelPort_setAddress': ParallelPort.cpp:(.text+0x96): undefined reference to `ioperm' ParallelPort.cpp:(.text+0xaa): undefined reference to `ioperm' Can anyone help me? Source follows. ParallelPort.java ---------- public class ParallelPort { static { System.loadLibrary("ParallelPort"); } public ParallelPort() { setAddress(0x378); // default to lp0 } public ParallelPort(int addr) { setAddress(addr); } public native void setAddress(int addr); public native int getAddress(); public native void sendData(int data); public native int readStatus(); public native void sendControl(int control); } ========== ParallelPort.cpp ---------- #include "ParallelPort.h" #include <jni.h> #include <stdio.h> #define extern static #define REALLY_SLOW_IO #include <asm/io.h> // port I/O #undef extern #include <sys/io.h> // for ioperm jint DATA; jint STATUS; jint CONTROL; JNIEXPORT void JNICALL Java_ParallelPort_setAddress(JNIEnv *env, jobject obj, jint addr) { DATA = addr; STATUS = addr + 1; CONTROL = addr +2; ioperm(DATA, 3, 1); ioperm(0x80, 1, 1); } JNIEXPORT jint JNICALL Java_ParallelPort_getAddress(JNIEnv *env, jobject obj) { return DATA; } JNIEXPORT void JNICALL Java_ParallelPort_sendData(JNIEnv *env, jobject obj, jint data) { outb(data, DATA); } JNIEXPORT jint JNICALL Java_ParallelPort_readStatus(JNIEnv *env, jobject obj) { return inb(STATUS); } JNIEXPORT void JNICALL Java_ParallelPort_sendControl(JNIEnv *env, jobject obj, jint control) { outb(control, CONTROL); } ========== ParallelPort.h (Auto-generated with javah) ---------- /* DO NOT EDIT THIS FILE - it is machine generated */ #include <jni.h> /* Header for class ParallelPort */ #ifndef _Included_ParallelPort #define _Included_ParallelPort #ifdef __cplusplus extern "C" { #endif /* * Class: ParallelPort * Method: setAddress * Signature: (I)V */ JNIEXPORT void JNICALL Java_ParallelPort_setAddress (JNIEnv *, jobject, jint); /* * Class: ParallelPort * Method: getAddress * Signature: ()I */ JNIEXPORT jint JNICALL Java_ParallelPort_getAddress (JNIEnv *, jobject); /* * Class: ParallelPort * Method: sendData * Signature: (I)V */ JNIEXPORT void JNICALL Java_ParallelPort_sendData (JNIEnv *, jobject, jint); /* * Class: ParallelPort * Method: readStatus * Signature: ()I */ JNIEXPORT jint JNICALL Java_ParallelPort_readStatus (JNIEnv *, jobject); /* * Class: ParallelPort * Method: sendControl * Signature: (I)V */ JNIEXPORT void JNICALL Java_ParallelPort_sendControl (JNIEnv *, jobject, jint); #ifdef __cplusplus } #endif #endif [/QUOTE]

Verification