f_write

The f_write writes data to a file.

FRESULT f_write (
  FIL* FileObject,     /* Pointer to the file object structure */
  const void* Buffer,  /* Pointer to the data to be written */
  UINT ByteToWrite,    /* Number of bytes to write */
  UINT* ByteWritten    /* Pointer to the variable to return number of bytes written */
);

Parameters

FileObject

Pointer to the open file object structure.

Buffer

Pointer to the data to be written.

ByteToWrite

Specifies number of bytes to write in range of UINT.

ByteWritten

Pointer to the UINT variable to return number of bytes written.

Return Values

FR_OK (0)

The function succeeded.

FR_DENIED

The function denied due to the file has been opened in non-write mode.

FR_DISK_ERR

The function failed due to an error in the disk function.

FR_INT_ERR

The function failed due to a wrong FAT structure 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 read/write pointer in the file object is increased in number of bytes written. After the function succeeded, *ByteWritten should be checked to detect disk full. In case of *ByteWritten < ByteToWrite, it means the disk got full during write operation.

This function is not available in read-only configuration.

References

f_open, f_read, fputc, fputs, fprintf, f_close, FIL