f_read

The f_read function reads data from a file.

FRESULT f_read (
  FIL* FileObject,    /* Pointer to the file object structure */
  void* Buffer,       /* Pointer to the buffer to store read data */
  WORD ByteToRead,    /* Number of bytes to read */
  WORD* ByteRead      /* Pointer to the variable to return number of bytes read */
);

Parameters

FileObject
Pointer to the open file object.
Buffer
Pointer to the buffer to store read data
ByteToRead
Number of bytes to read
ByteRead
Pointer to the WORD variable to return number of bytes read.

Return Values

FR_OK (0)
The function succeeded.
FR_DENIED
The function denied due to the file has been opened in write only mode.
FR_RW_ERROR
The function failed due to a disk error or an internal error.
FR_NOT_READY
The disk drive cannot work due to no medium in the drive or any other reason.
FR_INVALID_OBJECT
The file object is invalid.

Description

The file pointer in the file object increases in number of bytes read. The ByteRead will become less than ByteToRead when the read pointer reached to end of the file or any error occured during the read operation.

References

f_open, f_write, f_close, FIL

Return