cpusupportwin.c

来自「java线程2ED中文版 线程专业讲解」· C语言 代码 · 共 58 行

/*
 *
 * Copyright (c) 1997-1999 Scott Oaks and Henry Wong. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and
 * without fee is hereby granted.
 *
 * This sample source code is provided for example only,
 * on an unsupported, as-is basis. 
 *
 * AUTHOR MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. AUTHOR SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  AUTHOR
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */


#include <jni.h>
#include <windows.h>

JNIEXPORT jint JNICALL Java_CPUSupport_getNumProcessorsN(JNIEnv *env, jobject cls)
{
	static DWORD numCPU = 0;
	SYSTEM_INFO process_info;

	if (numCPU == 0) {
		GetSystemInfo(&process_info);
		numCPU = process_info.dwNumberOfProcessors;
	}
	return numCPU;
}

JNIEXPORT void JNICALL Java_CPUSupport_setConcurrencyN(JNIEnv *env, jobject cls, jint kthreads)
{
	// For Windows the concurrency is always infinity.
	return;
}

JNIEXPORT jint JNICALL Java_CPUSupport_getConcurrencyN(JNIEnv *env, jobject cls)
{
	// For Windows the concurrency is always infinity, but
	// we will return the number of processors instead.
	return Java_CPUSupport_getNumProcessorsN(env, cls);
}