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#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> int main(int argc, char *argv[]) { int fd = -1; int ret = 1; int buffer = 1024; int num = 0;
// O_CREAT: 当文件不存在时,创建一个新文件;O_RDWR: 以读写方式打开;O_TRUNC: 打开文件后,将文件的长度截断为0 if((fd=open("./test", O_RDWR|O_CREAT|O_TRUNC))==-1) { printf("Open Error "); exit(1); } ret = write(fd, &buffer, sizeof(int)); if( ret < 0) { printf("write Error "); exit(1); } printf("write %d byte(s) ",ret); lseek(fd, 0L, SEEK_SET); ret= read(fd, &num, sizeof(int)); if(ret==-1) { printf("read Error "); exit(1); } printf("read %d byte(s),the number is %d ", ret, num); close(fd); return 0; }