p10-12.c

SUN Solaris8平台下进程间通信

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h> /* mmap ()*/
#include <fcntl.h>
#include <stdio.h>
#define FILE_MODE 0666
int main(int argc, char *argv[] )
{
    int fdfrom , fdto;
    char *src, *dst;
    struct stat statbuf1,statbuf2;
    if (argc != 3)
        printf( "usage: a.out <fromfile> <tofile>\n" );
    /* 打开要连接的二个文件 */
    if ((fdfrom = open(argv[1], O_RDONLY)) < 0){
        printf("can't open %s for reading", argv[1]);
        exit(1);
    }
    if ((fdto = open(argv[2], O_RDWR|O_CREAT, FILE_MODE)) < 0){ 
        printf("can't creat %s for writing", argv[2]); 
        exit(1);
    }
    /* 获取这二个文件的大小*/
    if (fstat(fdfrom, &statbuf1) < 0){ /* need size of file1 */
        printf("fstat errort") ;
        exit(1);
    }
    if (fstat(fdto, &statbuf2) < 0){ /* need size of file2 */
        printf("fstat errort") ;
        exit(1);
    }
     /* 扩充输出文件的大小使之等于这二个文件大小之和 */
    if (lseek(fdto, statbuf1.st_size - 1, SEEK_END) == -1){
        printf("lseek error");
        exit(1);
    }
    /* 在文件尾部写一字符使扩充有效 */  
    if (write (fdto, "", 1) != 1){ 
        printf("write error") ;
        exit(1);
    }
    /* 映射这二个文件至内存 */
    if ((src = mmap(0, statbuf1.st_size, PROT_READ,
                   MAP_SHARED, fdfrom, 0)) == (caddr_t)-1){
        printf("mmap error for input") ;
        exit(1);
    }    
    if ((dst = mmap(0, statbuf2.st_size + statbuf1.st_size, 
                     PROT_READ | PROT_WRITE, MAP_SHARED, 
                     fdto, 0)) == (caddr_t)-1){
        printf("mmap error for output");
        exit(1);
    }    
    /* 连接第一个文件至第二个文件 */
    memcpy( dst+statbuf2.st_size, src, statbuf1.st_size);
    exit(0);
}