6.0 KiB
Print Format Specifiers
Lookup Table
We use the following format specifiers for all *printf* and WLog_* functions:
| Type | signed | unsigned | octal | hex | HEX |
|---|---|---|---|---|---|
| signed char | %hhd | ||||
| unsigned char | %hhu | %hho | %hhx | %hhX | |
| short | %hd | ||||
| unsigned short | %hu | %ho | %hx | %hX | |
| int | %d | ||||
| unsigned int | %u | %o | %x | %X | |
| long | %ld | ||||
| unsigned long | %lu | %lo | %lx | %lX | |
| long long | %lld | ||||
| unsigned long long | %llu | %llo | %llx | %llX | |
| size_t | %"PRIuz" | %"PRIoz" | %"PRIxz" | %"PRIXz" | |
| INT8 | %"PRId8" | ||||
| UINT8 | %"PRIu8" | %"PRIo8" | %"PRIx8" | %"PRIX8" | |
| BOOLEAN | %"PRIu8" | %"PRIo8" | %"PRIx8" | %"PRIX8" | |
| BYTE | %"PRIu8" | %"PRIo8" | %"PRIx8" | %"PRIX8" | |
| CHAR | %"PRId8" | ||||
| UCHAR | %"PRIu8" | %"PRIo8" | %"PRIx8" | %"PRIX8" | |
| INT16 | %"PRId16" | ||||
| UINT16 | %"PRIu16" | %"PRIo16" | %"PRIx16" | %"PRIX16" | |
| WORD | %"PRIu16" | %"PRIo16" | %"PRIx16" | %"PRIX16" | |
| WCHAR | %"PRIu16" | %"PRIo16" | %"PRIx16" | %"PRIX16" | |
| SHORT | %"PRId16" | ||||
| USHORT | %"PRIu16" | %"PRIo16" | %"PRIx16" | %"PRIX16" | |
| INT32 | %"PRId32" | ||||
| UINT32 | %"PRIu32" | %"PRIo32" | %"PRIx32" | %"PRIX32" | |
| INT | %"PRId32" | ||||
| UINT | %"PRIu32" | %"PRIo32" | %"PRIx32" | %"PRIX32" | |
| LONG | %"PRId32" | ||||
| HRESULT | %"PRId32" | %"PRIx32" | %"PRIX32" | ||
| NTSTATUS | %"PRId32" | %"PRIx32" | %"PRIX32" | ||
| ULONG | %"PRIu32" | %"PRIo32" | %"PRIx32" | %"PRIX32" | |
| DWORD | %"PRIu32" | %"PRIo32" | %"PRIx32" | %"PRIX32" | |
| DWORD32 | %"PRIu32" | %"PRIo32" | %"PRIx32" | %"PRIX32" | |
| BOOL | %"PRId32" | ||||
| INT64 | %"PRId64" | ||||
| LONG64 | %"PRId64" | ||||
| LONGLONG | %"PRId64" | ||||
| UINT64 | %"PRIu64" | %"PRIo64" | %"PRIx64" | %"PRIX64" | |
| ULONG64 | %"PRIu64" | %"PRIo64" | %"PRIx64" | %"PRIX64" | |
| ULONGLONG | %"PRIu64" | %"PRIo64" | %"PRIx64" | %"PRIX64" | |
| DWORDLONG | %"PRIu64" | %"PRIo64" | %"PRIx64" | %"PRIX64" | |
| QWORD | %"PRIu64" | %"PRIo64" | %"PRIx64" | %"PRIX64" | |
| ULONG64 | %"PRIu64" | %"PRIo64" | %"PRIx64" | %"PRIX64" |
Pointers
When printing pointers you should cast the argument to (void*):
rdpContext *pContext;
fprintf(stderr, "rdp context is %p\n", (void*) pContext);
If you need more formatting options cast the pointer argument to size_t and use
any %"PRI*z" format specifier:
rdpContext *pContext;
fprintf(stderr, "rdp context is %" PRIuz " (0x%" PRIXz ")\n", (size_t) pContext, (size_t) pContext);
Integer Promotion
Remember that integer types smaller than int are promoted when an operation is performed on them.
Wrong:
UINT8 a, b;
fprintf(stderr, "a - b is %" PRIu8 "\n", a - b);
// depending on the system's PRIu8 definition you might get:
// warning: format specifies type 'unsigned char' but the argument has type 'int'
Correct:
UINT8 a, b;
fprintf(stderr, "a - b is %d\n", a - b);
// or ...
fprintf(stderr, "a - b is %" PRIu8 "\n", (UINT8) (a - b));
TCHAR
When using _tprintf or similar TCHAR formatting functions or macros you
need to enclose the PRI format defines:
LPCTSTR lpFileName1;
UINT64 fileSize1;
_tprintf(_T("The size of %s is %") _T(PRIu64) _T("\n"), lpFileName1, fileSize1);
Since this makes the strings a lot harder to read try to avoid _tprintf if the arguments don't contain TCHAR types.
Note: If all compilers were C99 compliant we could simply write ...
_tprintf(_T("The size of %s is %") PRIu64 "\n"), lpFileName1, fileSize1);
... since the standard says that only one of the character sequences must be prefixed by an encoding prefix and the rest of them are treated to have the same. However, Microsoft Visual Studio versions older than VS 2015 are not C99 compliant in this regard.
See How to use stdint types with _tprintf in Visual Studio 2013 for more information.