FatFile Class Reference

Basic file class. More...

#include <FatFile.h>

Inheritance diagram for FatFile:

Public Member Functions
uint32_t	available ()
void	clearError ()
void	clearWriteError ()
bool	close ()
bool	contiguousRange (uint32_t *bgnBlock, uint32_t *endBlock)
bool	createContiguous (FatFile *dirFile, const char *path, uint32_t size)
bool	createContiguous (const char *path, uint32_t size)
uint32_t	curCluster () const
uint32_t	curPosition () const
bool	dirEntry (dir_t *dir)
uint16_t	dirIndex ()
uint32_t	dirSize ()
void	dmpFile (print_t *pr, uint32_t pos, size_t n)
bool	exists (const char *path)
	FatFile ()
	FatFile (const char *path, uint8_t oflag)
int16_t	fgets (char *str, int16_t num, char *delim=0)
uint8_t	fileAttr () const
uint32_t	fileSize () const
uint32_t	firstBlock ()
uint32_t	firstCluster () const
uint8_t	getError ()
bool	getName (char *name, size_t size)
void	getpos (FatPos_t *pos)
bool	getSFN (char *name)
bool	getWriteError ()
bool	isDir () const
bool	isFile () const
bool	isHidden () const
bool	isLFN () const
bool	isOpen () const
bool	isReadOnly () const
bool	isRoot () const
bool	isRoot32 () const
bool	isRootFixed () const
bool	isSubDir () const
bool	isSystem () const
void	ls (uint8_t flags=0)
void	ls (print_t *pr, uint8_t flags=0, uint8_t indent=0)
bool	mkdir (FatFile *dir, const char *path, bool pFlag=true)
bool	open (FatFileSystem *fs, const char *path, uint8_t oflag)
bool	open (FatFile *dirFile, uint16_t index, uint8_t oflag)
bool	open (FatFile *dirFile, const char *path, uint8_t oflag)
bool	open (const char *path, uint8_t oflag=O_READ)
bool	openNext (FatFile *dirFile, uint8_t oflag=O_READ)
bool	openRoot (FatVolume *vol)
int	peek ()
bool	printCreateDateTime (print_t *pr)
int	printField (float value, char term, uint8_t prec=2)
int	printField (int16_t value, char term)
int	printField (uint16_t value, char term)
int	printField (int32_t value, char term)
int	printField (uint32_t value, char term)
size_t	printFileSize (print_t *pr)
bool	printModifyDateTime (print_t *pr)
size_t	printName ()
size_t	printName (print_t *pr)
size_t	printSFN (print_t *pr)
int	read ()
int	read (void *buf, size_t nbyte)
int8_t	readDir (dir_t *dir)
bool	remove ()
bool	rename (FatFile *dirFile, const char *newPath)
void	rewind ()
bool	rmdir ()
bool	rmRfStar ()
bool	seekCur (int32_t offset)
bool	seekEnd (int32_t offset=0)
bool	seekSet (uint32_t pos)
void	setpos (FatPos_t *pos)
bool	sync ()
bool	timestamp (FatFile *file)
bool	timestamp (uint8_t flags, uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second)
bool	truncate (uint32_t length)
FatVolume *	volume () const
int	write (const char *str)
int	write (uint8_t b)
int	write (const void *buf, size_t nbyte)

Static Public Member Functions
static FatFile *	cwd ()
static void	dateTimeCallback (void(*dateTime)(uint16_t *date, uint16_t *time))
static void	dateTimeCallbackCancel ()
static uint8_t	dirName (const dir_t *dir, char *name)
static bool	legal83Char (uint8_t c)
static void	printFatDate (uint16_t fatDate)
static void	printFatDate (print_t *pr, uint16_t fatDate)
static void	printFatTime (uint16_t fatTime)
static void	printFatTime (print_t *pr, uint16_t fatTime)
static bool	remove (FatFile *dirFile, const char *path)
static bool	setCwd (FatFile *dir)

Detailed Description

Basic file class.

Constructor & Destructor Documentation

FatFile::FatFile ( )

inline

Create an instance.

FatFile::FatFile ( const char *  path, uint8_t  oflag  )

inline

Create a file object and open it in the current working directory.

Parameters

[in]	path	A path with a valid 8.3 DOS name for a file to be opened.
[in]	oflag	Values for oflag are constructed by a bitwise-inclusive OR of open flags. see FatFile::open(FatFile*, const char*, uint8_t).

Member Function Documentation

uint32_t FatFile::available ( )

inline

Returns

The number of bytes available from the current position to EOF for normal files. Zero is returned for directory files.

void FatFile::clearError ( )

inline

Clear all error bits.

void FatFile::clearWriteError ( )

inline

Set writeError to zero

bool FatFile::close

(

)

Close a file and force cached data and directory information to be written to the storage device.

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::contiguousRange	(	uint32_t *	bgnBlock,
		uint32_t *	endBlock
	)

Check for contiguous file and return its raw block range.

Parameters

[out]	bgnBlock	the first block address for the file.
[out]	endBlock	the last block address for the file.

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::createContiguous	(	FatFile *	dirFile,
		const char *	path,
		uint32_t	size
	)

Create and open a new contiguous file of a specified size.

Parameters

[in]	dirFile	The directory where the file will be created.
[in]	path	A path with a validfile name.
[in]	size	The desired file size.

Returns

The value true is returned for success and the value false, is returned for failure.

bool FatFile::createContiguous ( const char *  path, uint32_t  size  )

inline

Create and open a new contiguous file of a specified size.

Parameters

[in]	path	A path with a validfile name.
[in]	size	The desired file size.

Returns

The value true is returned for success and the value false, is returned for failure.

uint32_t FatFile::curCluster ( ) const

inline

Returns

The current cluster number for a file or directory.

uint32_t FatFile::curPosition ( ) const

inline

Returns

The current position for a file or directory.

static FatFile* FatFile::cwd ( )

inlinestatic

Returns

Current working directory

static void FatFile::dateTimeCallback ( void(*)(uint16_t *date, uint16_t *time)  dateTime )

inlinestatic

Set the date/time callback function

Parameters

[in]

dateTime

The user's call back function. The callback function is of the form:

void dateTime(uint16_t* date, uint16_t* time) {
  uint16_t year;
  uint8_t month, day, hour, minute, second;

  // User gets date and time from GPS or real-time clock here

  // return date using FAT_DATE macro to format fields
  *date = FAT_DATE(year, month, day);

  // return time using FAT_TIME macro to format fields
  *time = FAT_TIME(hour, minute, second);
}

Sets the function that is called when a file is created or when a file's directory entry is modified by sync(). All timestamps, access, creation, and modify, are set when a file is created. sync() maintains the last access date and last modify date/time.

See the timestamp() function.

static void FatFile::dateTimeCallbackCancel ( )

inlinestatic

Cancel the date/time callback function.

bool FatFile::dirEntry

(

dir_t *

dir

)

Return a file's directory entry.

Parameters

[out]

dir

Location for return of the file's directory entry.

Returns

The value true is returned for success and the value false is returned for failure.

uint16_t FatFile::dirIndex ( )

inline

Returns

The index of this file in it's directory.

uint8_t FatFile::dirName ( const dir_t *  dir, char *  name  )

static

Format the name field of dir into the 13 byte array name in standard 8.3 short name format.

Parameters

[in]	dir	The directory structure containing the name.
[out]	name	A 13 byte char array for the formatted name.

Returns

length of the name.

uint32_t FatFile::dirSize

(

)

Returns

The number of bytes allocated to a directory or zero if an error occurs.

void FatFile::dmpFile	(	print_t *	pr,
		uint32_t	pos,
		size_t	n
	)

Dump file in Hex

Parameters

[in]	pr	Print stream for list.
[in]	pos	Start position in file.
[in]	n	number of locations to dump.

bool FatFile::exists ( const char *  path )

inline

Test for the existence of a file in a directory

Parameters

[in]

path

Path of the file to be tested for.

The calling instance must be an open directory file.

dirFile.exists("TOFIND.TXT") searches for "TOFIND.TXT" in the directory dirFile.

Returns

true if the file exists else false.

int16_t FatFile::fgets	(	char *	str,
		int16_t	num,
		char *	delim = 0
	)

Get a string from a file.

fgets() reads bytes from a file into the array pointed to by str, until num - 1 bytes are read, or a delimiter is read and transferred to str, or end-of-file is encountered. The string is then terminated with a null byte.

fgets() deletes CR, '\r', from the string. This insures only a '\n' terminates the string for Windows text files which use CRLF for newline.

Parameters

[out]	str	Pointer to the array where the string is stored.
[in]	num	Maximum number of characters to be read (including the final null byte). Usually the length of the array str is used.
[in]	delim	Optional set of delimiters. The default is "\n".

Returns

For success fgets() returns the length of the string in str. If no data is read, fgets() returns zero for EOF or -1 if an error occurred.

uint8_t FatFile::fileAttr ( ) const

inline

Type of file. You should use isFile() or isDir() instead of fileType() if possible.

Returns

The file or directory type.

uint32_t FatFile::fileSize ( ) const

inline

Returns

The total number of bytes in a file.

uint32_t FatFile::firstBlock ( )

inline

Returns

first block of file or zero for empty file.

uint32_t FatFile::firstCluster ( ) const

inline

Returns

The first cluster number for a file or directory.

uint8_t FatFile::getError ( )

inline

Returns

All error bits.

bool FatFile::getName	(	char *	name,
		size_t	size
	)

Get a file's name followed by a zero byte.

Parameters

[out]	name	An array of characters for the file's name.
[in]	size	The size of the array in bytes. The array must be at least 13 bytes long. The file's name will be truncated if the file's name is too long.

Returns

The value true, is returned for success and the value false, is returned for failure.

void FatFile::getpos

(

FatPos_t *

pos

)

get position for streams

Parameters

[out]

pos

struct to receive position

bool FatFile::getSFN

(

char *

name

)

Get a file's Short File Name followed by a zero byte.

Parameters

[out]

name

An array of characters for the file's name. The array must be at least 13 bytes long.

Returns

The value true, is returned for success and the value false, is returned for failure.

bool FatFile::getWriteError ( )

inline

Returns

value of writeError

bool FatFile::isDir ( ) const

inline

Returns

True if this is a directory else false.

bool FatFile::isFile ( ) const

inline

Returns

True if this is a normal file else false.

bool FatFile::isHidden ( ) const

inline

Returns

True if this is a hidden file else false.

bool FatFile::isLFN ( ) const

inline

Returns

true if this file has a Long File Name.

bool FatFile::isOpen ( ) const

inline

Returns

True if this is an open file/directory else false.

bool FatFile::isReadOnly ( ) const

inline

Returns

True if file is read-only

bool FatFile::isRoot ( ) const

inline

Returns

True if this is the root directory.

bool FatFile::isRoot32 ( ) const

inline

Returns

True if this is the FAT32 root directory.

bool FatFile::isRootFixed ( ) const

inline

Returns

True if this is the FAT12 of FAT16 root directory.

bool FatFile::isSubDir ( ) const

inline

Returns

True if this is a subdirectory else false.

bool FatFile::isSystem ( ) const

inline

Returns

True if this is a system file else false.

static bool FatFile::legal83Char ( uint8_t  c )

inlinestatic

Check for a legal 8.3 character.

Parameters

[in]

c

Character to be checked.

Returns

true for a legal 8.3 character else false.

void FatFile::ls ( uint8_t  flags = 0 )

inline

List directory contents.

Parameters

[in]

flags

The inclusive OR of

LS_DATE - Print file modification date

LS_SIZE - Print file size.

LS_R - Recursive list of subdirectories.

void FatFile::ls	(	print_t *	pr,
		uint8_t	flags = 0,
		uint8_t	indent = 0
	)

List directory contents.

Parameters

[in]	pr	Print stream for list.
[in]	flags	The inclusive OR of

LS_DATE - Print file modification date

LS_SIZE - Print file size.

LS_R - Recursive list of subdirectories.

Parameters

[in]

indent

Amount of space before file name. Used for recursive list to indicate subdirectory level.

bool FatFile::mkdir	(	FatFile *	dir,
		const char *	path,
		bool	pFlag = true
	)

Make a new directory.

Parameters

[in]	dir	An open FatFile instance for the directory that will contain the new directory.
[in]	path	A path with a valid 8.3 DOS name for the new directory.
[in]	pFlag	Create missing parent directories if true.

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::open	(	FatFileSystem *	fs,
		const char *	path,
		uint8_t	oflag
	)

Open a file in the volume working directory of a FatFileSystem.

Parameters

[in]	fs	File System where the file is located.
[in]	path	with a valid 8.3 DOS name for a file to be opened.
[in]	oflag	bitwise-inclusive OR of open mode flags. See see FatFile::open(FatFile*, const char*, uint8_t).

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::open	(	FatFile *	dirFile,
		uint16_t	index,
		uint8_t	oflag
	)

Open a file by index.

Parameters

[in]	dirFile	An open FatFile instance for the directory.
[in]	index	The index of the directory entry for the file to be opened. The value for index is (directory file position)/32.
[in]	oflag	bitwise-inclusive OR of open mode flags. See see FatFile::open(FatFile*, const char*, uint8_t).

See open() by path for definition of flags.

Returns

true for success or false for failure.

bool FatFile::open	(	FatFile *	dirFile,
		const char *	path,
		uint8_t	oflag
	)

Open a file or directory by name.

Parameters

[in]	dirFile	An open FatFile instance for the directory containing the file to be opened.
[in]	path	A path with a valid 8.3 DOS name for a file to be opened.
[in]	oflag	Values for oflag are constructed by a bitwise-inclusive OR of flags from the following list

O_READ - Open for reading.

O_RDONLY - Same as O_READ.

O_WRITE - Open for writing.

O_WRONLY - Same as O_WRITE.

O_RDWR - Open for reading and writing.

O_APPEND - If set, the file offset shall be set to the end of the file prior to each write.

O_AT_END - Set the initial position at the end of the file.

O_CREAT - If the file exists, this flag has no effect except as noted under O_EXCL below. Otherwise, the file shall be created

O_EXCL - If O_CREAT and O_EXCL are set, open() shall fail if the file exists.

O_SYNC - Call sync() after each write. This flag should not be used with write(uint8_t) or any functions do character at a time writes since sync() will be called after each byte.

O_TRUNC - If the file exists and is a regular file, and the file is successfully opened and is not read only, its length shall be truncated to 0.

WARNING: A given file must not be opened by more than one FatFile object or file corruption may occur.

Note

Directory files must be opened read only. Write and truncation is not allowed for directory files.

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::open ( const char *  path, uint8_t  oflag = O_READ  )

inline

Open a file in the current working directory.

Parameters

[in]	path	A path with a valid 8.3 DOS name for a file to be opened.
[in]	oflag	bitwise-inclusive OR of open mode flags. See see FatFile::open(FatFile*, const char*, uint8_t).

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::openNext	(	FatFile *	dirFile,
		uint8_t	oflag = O_READ
	)

Open the next file or subdirectory in a directory.

Parameters

[in]	dirFile	An open FatFile instance for the directory containing the file to be opened.
[in]	oflag	bitwise-inclusive OR of open mode flags. See see FatFile::open(FatFile*, const char*, uint8_t).

Returns

true for success or false for failure.

bool FatFile::openRoot

(

FatVolume *

vol

)

Open a volume's root directory.

Parameters

[in]

vol

The FAT volume containing the root directory to be opened.

Returns

The value true is returned for success and the value false is returned for failure.

int FatFile::peek

(

)

Return the next available byte without consuming it.

Returns

The byte if no error and not at eof else -1;

bool FatFile::printCreateDateTime

(

print_t *

pr

)

Print a file's creation date and time

Parameters

[in]

pr

Print stream for output.

Returns

The value true is returned for success and the value false is returned for failure.

static void FatFile::printFatDate ( uint16_t  fatDate )

inlinestatic

Print a directory date field.

Format is yyyy-mm-dd.

Parameters

[in]

fatDate

The date field from a directory entry.

void FatFile::printFatDate ( print_t *  pr, uint16_t  fatDate  )

static

Print a directory date field.

Format is yyyy-mm-dd.

Parameters

[in]	pr	Print stream for output.
[in]	fatDate	The date field from a directory entry.

static void FatFile::printFatTime ( uint16_t  fatTime )

inlinestatic

Print a directory time field.

Format is hh:mm:ss.

Parameters

[in]

fatTime

The time field from a directory entry.

void FatFile::printFatTime ( print_t *  pr, uint16_t  fatTime  )

static

Print a directory time field.

Format is hh:mm:ss.

Parameters

[in]	pr	Print stream for output.
[in]	fatTime	The time field from a directory entry.

int FatFile::printField	(	float	value,
		char	term,
		uint8_t	prec = 2
	)

Print a number followed by a field terminator.

Parameters

[in]	value	The number to be printed.
[in]	term	The field terminator. Use '\n' for CR LF.
[in]	prec	Number of digits after decimal point.

Returns

The number of bytes written or -1 if an error occurs.

int FatFile::printField	(	int16_t	value,
		char	term
	)

Print a number followed by a field terminator.

Parameters

[in]	value	The number to be printed.
[in]	term	The field terminator. Use '\n' for CR LF.

Returns

The number of bytes written or -1 if an error occurs.

int FatFile::printField	(	uint16_t	value,
		char	term
	)

Print a number followed by a field terminator.

Parameters

[in]	value	The number to be printed.
[in]	term	The field terminator. Use '\n' for CR LF.

Returns

The number of bytes written or -1 if an error occurs.

int FatFile::printField	(	int32_t	value,
		char	term
	)

Print a number followed by a field terminator.

Parameters

[in]	value	The number to be printed.
[in]	term	The field terminator. Use '\n' for CR LF.

Returns

The number of bytes written or -1 if an error occurs.

int FatFile::printField	(	uint32_t	value,
		char	term
	)

Print a number followed by a field terminator.

Parameters

[in]	value	The number to be printed.
[in]	term	The field terminator. Use '\n' for CR LF.

Returns

The number of bytes written or -1 if an error occurs.

size_t FatFile::printFileSize

(

print_t *

pr

)

Print a file's size.

Parameters

[in]

pr

Print stream for output.

Returns

The number of characters printed is returned for success and zero is returned for failure.

bool FatFile::printModifyDateTime

(

print_t *

pr

)

Print a file's modify date and time

Parameters

[in]

pr

Print stream for output.

Returns

The value true is returned for success and the value false is returned for failure.

size_t FatFile::printName ( )

inline

Print a file's name.

Returns

The value true is returned for success and the value false is returned for failure.

size_t FatFile::printName

(

print_t *

pr

)

Print a file's name

Parameters

[in]

pr

Print stream for output.

Returns

The value true is returned for success and the value false is returned for failure.

size_t FatFile::printSFN

(

print_t *

pr

)

Print a file's Short File Name.

Parameters

[in]

pr

Print stream for output.

Returns

The number of characters printed is returned for success and zero is returned for failure.

int FatFile::read ( )

inline

Read the next byte from a file.

Returns

For success read returns the next byte in the file as an int. If an error occurs or end of file is reached -1 is returned.

int FatFile::read	(	void *	buf,
		size_t	nbyte
	)

Read data from a file starting at the current position.

Parameters

[out]	buf	Pointer to the location that will receive the data.
[in]	nbyte	Maximum number of bytes to read.

Returns

For success read() returns the number of bytes read. A value less than nbyte, including zero, will be returned if end of file is reached. If an error occurs, read() returns -1. Possible errors include read() called before a file has been opened, corrupt file system or an I/O error occurred.

int8_t FatFile::readDir

(

dir_t *

dir

)

Read the next directory entry from a directory file.

Parameters

[out]

dir

The dir_t struct that will receive the data.

Returns

For success readDir() returns the number of bytes read. A value of zero will be returned if end of file is reached. If an error occurs, readDir() returns -1. Possible errors include readDir() called before a directory has been opened, this is not a directory file or an I/O error occurred.

bool FatFile::remove

(

)

Remove a file.

The directory entry and all data for the file are deleted.

Note

This function should not be used to delete the 8.3 version of a file that has a long name. For example if a file has the long name "New Text Document.txt" you should not delete the 8.3 name "NEWTEX~1.TXT".

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::remove ( FatFile *  dirFile, const char *  path  )

static

Remove a file.

The directory entry and all data for the file are deleted.

Parameters

[in]	dirFile	The directory that contains the file.
[in]	path	Path for the file to be removed.

Note

This function should not be used to delete the 8.3 version of a file that has a long name. For example if a file has the long name "New Text Document.txt" you should not delete the 8.3 name "NEWTEX~1.TXT".

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::rename	(	FatFile *	dirFile,
		const char *	newPath
	)

Rename a file or subdirectory.

Parameters

[in]	dirFile	Directory for the new path.
[in]	newPath	New path name for the file/directory.

Returns

The value true is returned for success and the value false is returned for failure.

void FatFile::rewind ( )

inline

Set the file's current position to zero.

bool FatFile::rmdir

(

)

Remove a directory file.

The directory file will be removed only if it is empty and is not the root directory. rmdir() follows DOS and Windows and ignores the read-only attribute for the directory.

Note

This function should not be used to delete the 8.3 version of a directory that has a long name. For example if a directory has the long name "New folder" you should not delete the 8.3 name "NEWFOL~1".

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::rmRfStar

(

)

Recursively delete a directory and all contained files.

This is like the Unix/Linux 'rm -rf *' if called with the root directory hence the name.

Warning - This will remove all contents of the directory including subdirectories. The directory will then be removed if it is not root. The read-only attribute for files will be ignored.

Note

This function should not be used to delete the 8.3 version of a directory that has a long name. See remove() and rmdir().

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::seekCur ( int32_t  offset )

inline

Set the files position to current position + pos. See seekSet().

Parameters

[in]

offset

The new position in bytes from the current position.

Returns

true for success or false for failure.

bool FatFile::seekEnd ( int32_t  offset = 0 )

inline

Set the files position to end-of-file + offset. See seekSet(). Can't be used for directory files since file size is not defined.

Parameters

[in]

offset

The new position in bytes from end-of-file.

Returns

true for success or false for failure.

bool FatFile::seekSet

(

uint32_t

pos

)

Sets a file's position.

Parameters

[in]

pos

The new position in bytes from the beginning of the file.

Returns

The value true is returned for success and the value false is returned for failure.

static bool FatFile::setCwd ( FatFile *  dir )

inlinestatic

Set the current working directory.

Parameters

[in]

dir

New current working directory.

Returns

true for success else false.

void FatFile::setpos

(

FatPos_t *

pos

)

set position for streams

Parameters

[out]

pos

struct with value for new position

bool FatFile::sync

(

)

The sync() call causes all modified data and directory fields to be written to the storage device.

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::timestamp

(

FatFile *

file

)

Copy a file's timestamps

Parameters

[in]

file

File to copy timestamps from.

Note

Modify and access timestamps may be overwritten if a date time callback function has been set by dateTimeCallback().

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::timestamp	(	uint8_t	flags,
		uint16_t	year,
		uint8_t	month,
		uint8_t	day,
		uint8_t	hour,
		uint8_t	minute,
		uint8_t	second
	)

Set a file's timestamps in its directory entry.

Parameters

[in]

flags

Values for flags are constructed by a bitwise-inclusive OR of flags from the following list

T_ACCESS - Set the file's last access date.

T_CREATE - Set the file's creation date and time.

T_WRITE - Set the file's last write/modification date and time.

Parameters

[in]	year	Valid range 1980 - 2107 inclusive.
[in]	month	Valid range 1 - 12 inclusive.
[in]	day	Valid range 1 - 31 inclusive.
[in]	hour	Valid range 0 - 23 inclusive.
[in]	minute	Valid range 0 - 59 inclusive.
[in]	second	Valid range 0 - 59 inclusive

Note

It is possible to set an invalid date since there is no check for the number of days in a month.

Modify and access timestamps may be overwritten if a date time callback function has been set by dateTimeCallback().

Returns

The value true is returned for success and the value false is returned for failure.

bool FatFile::truncate

(

uint32_t

length

)

Truncate a file to a specified length. The current file position will be maintained if it is less than or equal to length otherwise it will be set to end of file.

Parameters

[in]

length

The desired length for the file.

Returns

The value true is returned for success and the value false is returned for failure.

FatVolume* FatFile::volume ( ) const

inline

Returns

FatVolume that contains this file.

int FatFile::write ( const char *  str )

inline

Write a string to a file. Used by the Arduino Print class.

Parameters

[in]

str

Pointer to the string. Use getWriteError to check for errors.

Returns

count of characters written for success or -1 for failure.

int FatFile::write ( uint8_t  b )

inline

Write a single byte.

Parameters

[in]

b

The byte to be written.

Returns

+1 for success or -1 for failure.

int FatFile::write	(	const void *	buf,
		size_t	nbyte
	)

Write data to an open file.

Note

Data is moved to the cache but may not be written to the storage device until sync() is called.

Parameters

[in]	buf	Pointer to the location of the data to be written.
[in]	nbyte	Number of bytes to write.

Returns

For success write() returns the number of bytes written, always nbyte. If an error occurs, write() returns -1. Possible errors include write() is called before a file has been opened, write is called for a read-only file, device is full, a corrupt file system or an I/O error.

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The documentation for this class was generated from the following files:

• Arduino/libraries/SdFat/src/FatLib/FatFile.h
• Arduino/libraries/SdFat/src/FatLib/FatFile.cpp
• Arduino/libraries/SdFat/src/FatLib/FatFileLFN.cpp
• Arduino/libraries/SdFat/src/FatLib/FatFilePrint.cpp
• Arduino/libraries/SdFat/src/FatLib/FatFileSFN.cpp