#include<stdio.h>
    #include<stdlib.h>
    #include<fcntl.h>
    #include<unistd.h>
    #include<string.h>

    int main(int argc, char* argv[]) {
    	int f,n;
		unsigned int x;
		unsigned long int i, offset, l;
    	memset(tst,0,256);
    		if(argc<4){
    			printf("erreur : %s <file_name> <32-bit int in Hex> <Offset in Hex>\n",argv[0]);
    			exit(1);
    		}
    	f=open(argv[1],O_WRONLY);
    		if(f==-1){
    			perror("Opening failed");
    			exit(2);
    		}
    	x= (unsigned int)strtol(argv[2],NULL,16);
		i= (unsigned int)strtol(argv[3],NULL,16);
		offset = i*sizeof(int);
    	l=lseek(f,0,SEEK_END);
		if (offset > l) offset =l;
		l=lseek(f,offset,SEEK_SET);
    	if(l==-1){
    			perror("erreur dans lseek");
    			exit(2);
    		}    	
    	ents = strtol(argv[2],NULL,16);
    	write(f,&x,sizeof(int));
    	close(f);
    	return EXIT_SUCCESS;
    }