file_fopen.tex

efsl-0.3.6.zip

\subsubsection*{Purpose}
Searches for file and initializes the file object.
\subsubsection*{Prototype}
\code{esint8 file\_fopen(File *file, FileSystem *fs, eint8 *filename, eint8 mode);}
\subsubsection*{Arguments}
Objects passed to \code{file\_fopen}:
\begin{itemize}
	\item{\code{file}: pointer to a File object}
	\item{\code{fs}: pointer to the FileSystem object}
	\item{\code{filename}: pointer to the path + filename}
	\item
	{
		\code{mode}: mode of opening, this can be:
		\begin{itemize}
			\item{'r': open file for reading}
			\item{'w': open file for writing}
			\item{'a': open file for appending}
		\end{itemize}
	}
\end{itemize}
\subsubsection*{Return value}
Returns 0 if no errors are detected.\\
\newline
Returns non-zero if an error is detected:
\begin{itemize}
	\item{Returns -1 if the file you are trying to open for reading could not 
		be found.}
	\item{Returns -2 if the file you are trying to open for writing already
		exists.}
	\item{Returns -3 if no free spot could be found for writing or appending.}
	\item{Returns -4 if mode is not correct (if it is not 'r', 'w' or 'a').}
\end{itemize}
\subsubsection*{Example}
\lstset{numbers=left, stepnumber=1, numberstyle=\small, numbersep=5pt, tabsize=4}
\begin{lstlisting}
	#include "efs.h"

	void main(void)
	{
		EmbeddedFileSystem efsl;
		File file_read, file_write;

		/* Initialize efsl */
		DBG((TXT("Will init efsl now.\n")));
		if(efs_init(&efsl,"/dev/sda")!=0){
			DBG((TXT("Could not initialize filesystem (err \%d).\n"),ret));
			exit(-1);
		}
		DBG((TXT("Filesystem correctly initialized.\n")));

		/* Open file for reading */
		if(file_fopen(&file_read, &efsl.myFs, "read.txt", 'r')!=0){
			DBG((TXT("Could not open file for reading.\n")));
			exit(-1);
		}
		DBG((TXT("File opened for reading.\n")));

		/* Open file for writing */
		if(file_fopen(&file_write, &efsl.myFs, "write.txt", 'w')!=0){
			DBG((TXT("Could not open file for writing.\n")));
			exit(-2);
		}
		DBG((TXT("File opened for writing.\n")));

		/* Close files & filesystem */
		fclose(&file_read);
		fclose(&file_write);
		fs_umount(&efs.myFs);
	}
\end{lstlisting}