The header file fatfs/vfs/esp_vfs_fat.h defines the functions for connecting FatFs and VFS. This allows mapping of FatFs drives to physical disks at runtime. Although the library can be used directly, many of its features can be accessed via VFS using the C standard library and POSIX API functions.Īdditionally, FatFs has been modified to support the runtime pluggable disk I/O layer. ESP-IDF uses the FatFs library to work with FAT filesystems.