|GNU Octave Manual Version 3|
by John W. Eaton, David Bateman, Søren Hauberg
Paperback (6"x9"), 568 pages
RRP £24.95 ($39.95)
14.2.18 End of File and Errors
Once a file has been opened its status can be acquired. As an example
feof functions determines if the end of the file has been
reached. This can be very useful when reading small parts of a file
at a time. The following example shows how to read one line at a time
from a file until the end has been reached.
filename = "myfile.txt"; fid = fopen (filename, "r"); while (! feof (fid) ) text_line = fgetl (fid); endwhile fclose (fid);
Note that in some situations it is more efficient to read the entire contents of a file and then process it, than it is to read it line by line. This has the potential advantage of removing the loop in the above code.
- 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.
See also fread, fopen, fclose
- 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
|ISBN 095461206X||GNU Octave Manual Version 3||See the print edition|