not a typewriter error

I am getting the error "not a typewriter" when my program invokes the
sscanf function. What does this error imply and how can I get past it ?

Thanks in advance.

check this out
http://c-faq.com/stdio/printferrno.html

I got this from google. It appears that something is wrong with the IO. insufficient permissions probably

sscanf, did you say? can you send the sscanf line and the way you have defined the variables used in your sscanf statement.

C functions that write to a device or a file return the error
ENOTTY - the error responsible for 'Not a typewriter'.

sscanf reads data. It does return that error number.

errno, once set by an error, is left unchanged until another error happens.
That means if printf posted the error, but you checked the error later, right
after the sscanf() call, it would look to you like sscanf() failed.