LINUX C 文件读写范例

 

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <sys/types.h>
 4 #include <sys/stat.h>
 5 
 6 #include <sys/fcntl.h>   //file
 7 
 8 #define PCFILE  "/root/wencal"
 9 #define PCBACKFILE "/root/wencal_back"
10 
11 int main(void)
12 {
13     int ret;
14     int size;
15     
16     FILE * Ppointercal;
17     FILE * Ppointercal_back;
18     void * filebuffer;
19 
20     int pointercal_fd ;
21 
22     char modeR='r';
23     char modeW='w';
24 
25     struct stat st;
26 
27     pointercal_fd = open(PCFILE, O_RDONLY);
28     if (pointercal_fd < 0) {
29         printf("Input file open error\n");
30         return -1;
31     }
32     fstat(pointercal_fd,&st);
33     size = st.st_size;
34     close(pointercal_fd);
35 
36     filebuffer=(void *)malloc(size);
37 
38     Ppointercal = fopen(PCFILE,&modeR);
39     Ppointercal_back = fopen(PCBACKFILE,&modeW);
40     ret=fread(filebuffer,1,size,Ppointercal); //1 表示单位为1个字节
41 
42     if(ret == size)
43     {
44         printf("read success :%d \n",size);
45         fwrite(filebuffer,1,size,Ppointercal_back);
46     }
47     else 
48     {
49         printf("read err :  %d\n",size);    
50     }
51     
52     free(filebuffer);
53     fclose(Ppointercal);
54     fclose(Ppointercal_back);
55     return 0;
56 }