In C-language, what are the most appropriate format specifiers for data type BYTE, WORD and DWORD to be used with printf and scanf functions? I am having a hard time displaying BPB field's values over console.
For example, if I am trying to display BPB_BytsPerSec using "%lu", I am getting unusual figures..
printf("Bytes per Sector: %lu", b->BPB_BytsPerSec);
I am getting a value of "514", which I believe, is wrong interpretation.. Please suggest the way out. Thanks.
(I am using gcc 5.1 via MinGW, over a 64bit Windows)
Here is the Structure We are talking about:
/* BPB Structure Collected from internet */
struct BPB_FAT32 {
BYTE BS_jmpBoot[3]; // 0
BYTE BS_OEMName[8]; // 3
WORD BPB_BytsPerSec; // 11
BYTE BPB_SecPerClus; // 13
WORD BPB_ResvdSecCnt; // 14
BYTE BPB_NumFATs; // 16
WORD BPB_RootEntCnt; // 17
WORD BPB_TotSec16; // 19
BYTE BPB_Media; // 21
WORD BPB_FATSz16; // 22
WORD BPB_SecPerTrk; // 24
WORD BPB_NumHeads; // 26
DWORD BPB_HiddSec; // 28
DWORD BPB_TotSec32; // 32
DWORD BPB_FATSz32; // 36
WORD BPB_ExtFlags; // 40
WORD BPB_FSVer; // 42
DWORD BPB_RootClus; // 44
WORD BPB_FSInfo; // 48
WORD BPB_BkBootSec; // 50
BYTE BPB_Reserved[12]; // 52
BYTE BS_DrvNum; // 64
BYTE BS_Reserved1; // 65
BYTE BS_BootSig; // 66
DWORD BS_VolID; // 67
BYTE BS_VolLab[11]; // 71
BYTE BS_FilSysType[8]; // 82
};
And this the function through which i am trying to display these values..
void DisplayBlock(struct BPB_FAT32* b){
printf("\n\n\t1. Jump to boot code..........: 0x%02x%02x%02x",b->BS_jmpBoot[0],b->BS_jmpBoot[1],b->BS_jmpBoot[2]);
printf("\n\n\t2. OEM name & version.........: "); for(int i=0; i<8;i++) printf("%c",(char)b->BS_OEMName[i]);
printf("\n\n\t3. Bytes per Sector...........: %u",b->BPB_BytsPerSec); // WORD
printf("\n\n\t4. Sectors per Cluster........: %lu", b->BPB_SecPerClus); // BYTE
printf("\n\n\t5. Reserved Sectors Count.....: %lu", b->BPB_ResvdSecCnt); // WORD
printf("\n\n\t6. Number of FAT32 tables.....: %u", b->BPB_NumFATs); // BYTE
printf("\n\n\t7. Number of Root Entries.....: %lu", b->BPB_RootEntCnt); // WORD
printf("\n\n\t8. Total Sectors 16bits.......: %lu",b->BPB_TotSec16); // WORD
printf("\n\n\t9. Media Descriptor...........: %lu",b->BPB_Media); // BYTE 0xF8 is the standard value for fixed media
printf("\n\n\t10. Size According to FAT16....: %lu",b->BPB_FATSz16); // WORD
printf("\n\n\t11. Number of Sector per Track.: %lu",b->BPB_SecPerTrk); // WORD
printf("\n\n\t12. Number of Heads............: %lu",b->BPB_NumHeads); // WORD
printf("\n\n\t13. Number of Hidden Sectors...: %lu", b->BPB_HiddSec); // DWORD
printf("\n\n\t14. Total Sectors 32bits.......: %lu", b->BPB_TotSec32); // DWORD
/* FAT32 Specific Fields Starting offset:36 */
printf("\n\n\t15. Size According to FAT32....: %lu", b->BPB_FATSz32); // DWORD
//printf("\n\n\t16. Extended Flags............: %u",b->BPB_ExtFlags); // WORD Usually 0.
printf("\n\n\t17. File System Version........: %lu", b->BPB_FSVer); // WORD Must be 0:0
printf("\n\n\t18. Root Cluster Number........: %lu",b->BPB_RootClus); // DWORD Usually 2
printf("\n\n\t19. File System Information....: %lu",b->BPB_FSInfo); // WORD
printf("\n\n\t20. Backup Boot Sector.........: %lu",b->BPB_BkBootSec); // WORD Recomended 6
// BYTE BPB_Reserved[12]
/* Remaining common fields FAT12/FAT16 BPB*/
printf("\n\n\t21. Drive Number...............: %u",b->BS_DrvNum); // BYTE
// BYTE BS_Reserved1; /* 65 reserved */
printf("\n\n\t22. Boot Signature.............: %u",b->BS_BootSig); // BYTE
printf("\n\n\t23. Volume ID..................: %lu",b->BS_VolID); // DWORD
printf("\n\n\t24. Volume Lable...............: %s",b->BS_VolLab); //for(int i=0;i<11;i++) printf("%c",b->BS_VolLab[i]); // BYTE [11]
printf("\n\n\t25. File System Type...........: "); for(int i=0;i<8;i++) printf("%c",b->BS_FilSysType[i]); // BYTE [8]
}
typedef unsigned char BYTE;
typedef unsigned short WORD;
typedef unsigned long DWORD;
typedef unsigned long long QWORD;
来源:https://stackoverflow.com/questions/38283855/format-specifiers-for-data-type-byte-word-and-dword-in-c-language