mmap的使用之两个进程通过映射普通文件实现共享内存通信

/*-------------map_normalfile1.c-----------*/
#include	<sys/mman.h>
#include	<sys/types.h>
#include	<fcntl.h>
#include	<string.h>
#include	<stdio.h>
#include	<unistd.h>

typedef struct{
char name[4];
int age;
}  people;

//mmap_normal_file1.c 两个进程通过映射普通文件实现共享内存通信
void main(int argc, char **argv)//map a normal file as shared mem:
{
int fd,i;
people *p_map;
char temp;
char data[64];
fd = open(argv[1], O_CREAT | O_RDWR | O_TRUNC, 00777);
lseek(fd, sizeof(people) * 5 - 1, SEEK_SET);
write(fd, "", 1);
//把文件映射到共享内存
p_map = (people*)mmap(NULL, sizeof(people) * 10, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
close(fd);
temp = 'a';
for(i=0;i<10;i++)
{
temp += 1;
sprintf(data, "exe%c", temp);
memcpy((*(p_map + i)).name, &data, strlen(data));
(*(p_map + i)).age = 20 + i;
}
printf("initializeover  write finish \n");
sleep(10);
munmap(p_map, sizeof(people) * 10);
printf("umap ok\n");
}

/*-------------map_normalfile2.c-----------*/
#include <sys/mman.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>

typedef struct {
char name[4];
int age;
}people;

//mmap_normal_file2.c 两个进程通过映射普通文件实现共享内存通信
void main(int argc, char **argv)//map a normal file as shared mem:
{

int fd, i;
people *p_map;
fd = open(argv[1], O_CREAT | O_RDWR, 00777);
p_map = (people*)mmap(NULL, sizeof(people) * 10, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
for(i = 0 ; i < 10 ; i++)
{

printf("read data name=%s age=%d;\n", (*(p_map + i)).name, (*(p_map + i)).age);
}
munmap(p_map, sizeof(people) * 10);

}

#Generated by VisualGDB project wizard.
#Note: VisualGDB will automatically update this file when you add new sources to the project.
#CMakeList.txt
cmake_minimum_required(VERSION 2.7)
project(LinuxProject1)
set(LIBRARIES_FROM_REFERENCES "")
add_executable(mmap_normal_file1 mmap_normal_file1.c)
add_executable(mmap_normal_file2 mmap_normal_file2.c)
target_link_libraries(mmap_normal_file1 "${LIBRARIES_FROM_REFERENCES}")
target_link_libraries(mmap_normal_file2 "${LIBRARIES_FROM_REFERENCES}")