— Built-in Function: feof (fid)

Return 1 if an end-of-file condition has been encountered for a given file and 0 otherwise. Note that it will only return 1 if the end of the file has already been encountered, not if the next read operation will result in an end-of-file condition.

— Built-in Function: ferror (fid)

Return 1 if an error condition has been encountered for a given file and 0 otherwise. Note that it will only return 1 if an error has already been encountered, not if the next operation will result in an error condition.

— Built-in Function: freport ()

Print a list of which files have been opened, and whether they are open for reading, writing, or both. For example,

          freport ()
          
               -|  number  mode  name
               -|
               -|       0     r  stdin
               -|       1     w  stdout
               -|       2     w  stderr
               -|       3     r  myfile