This documentation is copyright © 1998-2001 Sandro Sigala <sandro@sigala.it>.
All rights reserved.

Released under the GNU General Public License.

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fopen

Prototype

#include <stdio.h>

FILE *fopen(const char *filename, const char *mode);

Description

Opens the specified file filename and returns a stream associated with it. If the open operation fails, returns NULL. The mode string specifies the operations that might be done on the stream, as summarized by the \vpageref[table below][table ]{tbl:fopen_modes}: \begin{table}[!htp] \begin{center} \begin{tabular}{|l|p{10cm}|} \hline \hline \textsc{Mode} & \textsc{Description} \\ \hline \texttt{r} & Open text file for reading \\ \texttt{w} & Truncate to zero length or create text file for writing \\ \texttt{a} & Append; open or create text file for writing at end-of-file \\ \texttt{rb} & Open binary file for reading \\ \texttt{wb} & Truncate to zero length or create binary file for writing \\ \texttt{ab} & Append; open or create binary file for writing at end-of-file \\ \texttt{r+} & Open text file for update (reading and writing) \\ \texttt{w+} & Truncate to zero length or create text file for update, writing at end-of-file \\ \texttt{a+} & Append; open or create text file for update, writing at end-of-file \\ \texttt{r+b} \textit{or} \texttt{rb+} & Open binary file for update (reading and writing) \\ \texttt{w+b} \textit{or} \texttt{wb+} & Truncate to zero length or create binary file for update, writing at end-of-file \\ \texttt{a+b} \textit{or} \texttt{ab+} & Append; open or create binary file for update, writing at end-of-file \\ \hline \end{tabular} \caption{The \texttt{fopen} opening modes.} \label{tbl:fopen_modes} \end{center} \end{table}

References

ISO C 9899:1990 7.9.5.2