how to write a struct to a file directly?
Using write and read system call. Following is an example:
blk.h:
#include <stdlib.h> #include <stdio.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> #include <string.h> struct data{ char s[20]; int d1; char c; }; #define BLK_SIZE 25
writeb.c:
#include "blk.h" int main(){ struct data *d= malloc(BLK_SIZE); d->d1= 8; d->c= 'a'; strcpy(d->s, "first try.."); int fd= open("blk.dat", O_RDWR | O_CREAT | O_EXCL, S_IREAD | S_IWRITE); write(fd, d, BLK_SIZE); printf("writed!\n"); close(fd); return 0; }
readb.c:
include "blk.h" int main(){ int fd; struct data *d; fd= open("blk.dat", O_RDWR); read(fd, d, BLK_SIZE); printf("%d, %c, %s\n", d->d1, d->c, d->s); close(fd); return 0; }