Free Knowledge Resources


Linux Manual Pages


Free Software * Books

Source Code

Free Media

Linux

clearerr(3)


NAME

   clearerr, feof, ferror, fileno - check and reset stream status

SYNOPSIS

   #include <stdio.h>

   void clearerr(FILE *stream);

   int feof(FILE *stream);

   int ferror(FILE *stream);

   int fileno(FILE *stream);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   fileno(): _POSIX_C_SOURCE

DESCRIPTION

   The function clearerr() clears the end-of-file and error indicators for
   the stream pointed to by stream.

   The function feof() tests the  end-of-file  indicator  for  the  stream
   pointed  to by stream, returning nonzero if it is set.  The end-of-file
   indicator can be cleared only by the function clearerr().

   The function ferror() tests the error indicator for the stream  pointed
   to  by stream, returning nonzero if it is set.  The error indicator can
   be reset only by the clearerr() function.

   The function fileno() examines the  argument  stream  and  returns  its
   integer file descriptor.

   For nonlocking counterparts, see unlocked_stdio(3).

ERRORS

   These  functions  should  not fail and do not set the external variable
   errno.  (However, in case fileno() detects that its argument is  not  a
   valid stream, it must return -1 and set errno to EBADF.)

ATTRIBUTES

   For   an   explanation   of   the  terms  used  in  this  section,  see
   attributes(7).

   
   Interface            Attribute      Value   
   
   clearerr(), feof(),  Thread safety  MT-Safe 
   ferror(), fileno()

CONFORMING TO

   The functions clearerr(), feof(), and ferror()  conform  to  C89,  C99,
   POSIX.1-2001, and POSIX.1-2008.

   The function fileno() conforms to POSIX.1-2001 and POSIX.1-2008.

SEE ALSO

   open(2), fdopen(3), stdio(3), unlocked_stdio(3)

COLOPHON

   This  page  is  part of release 4.09 of the Linux man-pages project.  A
   description of the project, information about reporting bugs,  and  the
   latest     version     of     this    page,    can    be    found    at
   https://www.kernel.org/doc/man-pages/.

                              2016-03-15                         FERROR(3)



Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.



Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.



Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.



Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.


birds banner