hi i am new to c programming and found this on the net could someone tell me what it actually does, many thanks in advance cheers


#include <fcntl.h>
main()
{
int fd;

fd = open("in1", O_RDONLY);
printf("%d\n", fd);
}

and this too please



#include <fcntl.h>
main()
{
int fd;

fd = open("in1", O_WRONLY);
if(fd < 0)
{
perror("filename");
exit(1);
}

}

First one: open file "in1" read-only and print out the file descriptor (file handle)
Second: open file "in1" write-only and if open() returns a negative number (like -1) that means it cannot be open()ed. Show error message and quit.