Linux使用mmap调用创建、读写和释放共享内存区域

#include <sys/mman.h>
void *mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset);

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>

int main() {
    // 定义映射区域大小
    size_t size = 4096;
    
    // 使用mmap创建匿名共享内存
    void *mapped = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
    
    // 检查映射是否成功
    if (mapped == MAP_FAILED) {
        perror("mmap failed");
        return 1;
    }
    
    printf("Memory mapped at address %p\n", mapped);
    
    // 使用共享内存...
    
    // 释放映射区
    if (munmap(mapped, size) == -1) {
        perror("munmap failed");
        return 1;
    }
    
    return 0;
}

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

int main() {
    // 定义映射区域大小
    size_t size = 4096;
    
    // 使用mmap创建匿名共享内存
    void *mapped = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
    
    // 检查映射是否成功
    if (mapped == MAP_FAILED) {
        perror("mmap failed");
        return 1;
    }
    
    // 写入数据到映射区
    char *message = "Hello, shared memory!";
    strncpy((char *)mapped, message, strlen(message));
    
    // 读取并打印映射区内容
    printf("Read from shared memory: %s\n", (char *)mapped);
    
    // 释放映射区
    if (munmap(mapped, size) == -1) {
        perror("munmap failed");
        return 1;
    }
    
    return 0;
}

#include <sys/mman.h>
int munmap(void *addr, size_t length);

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>

int main() {
    // 定义映射区域大小
    size_t size = 4096;
    
    // 使用mmap创建匿名共享内存
    void *mapped = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
    
    // 检查映射是否成功
    if (mapped == MAP_FAILED) {
        perror("mmap failed");
        return 1;
    }
    
    // 使用共享内存...
    
    // 释放映射区
    if (munmap(mapped, size) == -1) {
        perror("munmap failed");
        return 1;
    }
    
    printf("Memory unmapped successfully\n");
    return 0;
}