The f_getfree function gets number of the free clusters.
FRESULT f_getfree ( const TCHAR* path, /* [IN] Logical drive number */ DWORD* nclst, /* [OUT] Number of free clusters */ FATFS** fatfs /* [OUT] Corresponding file system object */ );
FR_OK, FR_DISK_ERR, FR_INT_ERR, FR_NOT_READY, FR_INVALID_DRIVE, FR_NOT_ENABLED, FR_NO_FILESYSTEM, FR_TIMEOUT
The f_getfree() function gets number of free clusters on the volume. The member csize in the file system object indicates number of sectors per cluster, so that the free space in unit of sector can be calcurated with this information. When FSINFO structure on the FAT32 volume is not in sync, this function can return an incorrect free cluster count. To avoid this problem, FatFs can be forced full FAT scan by _FS_NOFSINFO option.
Available when _FS_READONLY == 0 and _FS_MINIMIZE == 0.
FATFS *fs; DWORD fre_clust, fre_sect, tot_sect; /* Get volume information and free clusters of drive 1 */ res = f_getfree("1:", &fre_clust, &fs); if (res) die(res); /* Get total sectors and free sectors */ tot_sect = (fs->n_fatent - 2) * fs->csize; fre_sect = fre_clust * fs->csize; /* Print the free space (assuming 512 bytes/sector) */ printf("%10lu KiB total drive space.\n%10lu KiB available.\n", tot_sect / 2, fre_sect / 2);