All Identifiers

Directory

LFN entry

Read only

Volume label

Directory object structure

Read Partial Sector

File system object structure

File status structure

Move file pointer of the open file

The pf_lseek() function moves the file read/write pointer of the open file. The ofs can be specified in only origin from top of the file.

Opens an existing file

The file must be opend prior to use pf_read and pf_lseek function. The open file is valid until next open.

Read data from the open file.

The file read/write pointer in the file system object advances in number of bytes read. After the function succeeded, br should be checked to detect end of file. In case of br is less than btr, it means the read pointer has reached end of the file during read operation. If a null pointer is given to the buff, the read data bytes are forwarded to the outgoing stream instead of the memory. The streaming function depends on each project will be typically built-in the disk_readp function.

Directory rewind.

Write data to the open file. The write function has some restrictions listed below:

Cannot create file. Only existing file can be written. Cannot expand file size. Cannot update time stamp of the file. Write operation can start/stop on the sector boundary only. Read-only attribute of the file cannot block write operation.

The read/write pointer in the file system object advances in number of bytes written. After the function succeeded, bw should be checked to detect end of file. In case of bw is less than btw, it means the read/write pointer reached end of file during the write operation. Once a write operation is initiated, it must be finalized properly, or the written data can be lost.

No medium in the drive