linux共享内存的读写问题！！
//共享内存区段的挂载,脱离和使用
//理解共享内存区段就是一块大内存
#include <stdio.h>
#include <sys/shm.h>
#include <sys/ipc.h>
#include <errno.h>
#define MY_SHM_ID 67483
int main( )
{
//共享内存区段的挂载和脱离
int shmid,ret;
void* mem;
shmid=shmget( MY_SHM_ID,0,0 );
if( shmid>=0 )
{
mem=shmat( shmid,( const void* )0,0 );
//shmat()返回进程地址空间中指向区段的指针
if( ( int )mem!=-1 )
{
printf( "Shared memory was attached in our address space at %p/n",mem );
//向共享区段内存写入数据
strcpy( ( char* )mem,"This is a test string./n" );
printf( "%s/n",(char*)mem );
//脱离共享内存区段
ret=shmdt( mem );
if( ret==0 )
printf( "Successfully detached memory /n" );
else
printf( "Memory detached failed %d/n",errno );
}
else
printf( "shmat( ) failed/n" );
}
else
printf( "shared memory segment not found/n" );
return 0;
}
