int
main(int argc, char *argv[])
{
int fd;
time_t now;
char *msg;
if (argc != 2) {
fprintf(stderr, "Usage: %s <filename>\n", argv[0]);
exit(1);
}
if ((fd = open(argv[1], O_CREAT | O_TRUNC | O_WRONLY, 0644)) == -1)
oops(argv[1], 2);
while (1) {
time(&now);
msg = ctime(&now);
lock_operation(fd, F_WRLCK); /* lock for writing */
if (lseek(fd, 0, SEEK_SET) == -1)
oops("lseek", 3);
if (write(fd, msg, strlen(msg)) == -1)
oops("write", 4);
lock_operation(fd, F_UNLCK); /* unlock file */
sleep(1);
}
close(fd);
return 0;
}
int main(int argc,char* argv[])
{
int fd,nread;
char buf[BUFLEN];
if(argc!=2){
fprintf(stderr,"usage:./file_tc filename\n");
exit(1);
}
fd=open(argv[1],O_RDONLY);
if(fd==-1) oops(argv[1],O_RDONLY);
lock_operation(fd,F_RDLCK);
while((nread=read(fd,buf,BUFLEN))>0){
write(STDOUT_FILENO,buf,nread);
}
lock_operation(fd,F_UNLCK);
close(fd);
}
/**
* Releases advisory, exclusive lock on given file (FILE *).
*/
void File_UnLock(FILE *fp)
{
lock_operation(fp, DO_UNLOCK);
}
/**
* Takes advisory, exclusive lock on given file (FILE *).
* Returns false if locking fails (e.g. another Hatari
* instance has already file open for writing).
*/
bool File_Lock(FILE *fp)
{
return lock_operation(fp, DO_LOCK);
}
