|**`a`**|Floating-point|Signed hexadecimal double-precision floating-point value that has the form [-]0x*`h.hhhh`*__p±__*`dd`*, where *`h.hhhh`* are the hex digits (using lower case letters) of the mantissa, and *`dd`* are one or more digits for the exponent. The precision specifies the number of digits after the point.|

|**`A`**|Floating-point|Signed hexadecimal double-precision floating-point value that has the form [-]0X*`h.hhhh`*__P±__*`dd`*, where *`h.hhhh`* are the hex digits (using capital letters) of the mantissa, and *dd* are one or more digits for the exponent. The precision specifies the number of digits after the point.|

|**`Z`**|`ANSI_STRING` or `UNICODE_STRING` structure|When the address of an [ANSI_STRING](/windows/win32/api/ntdef/ns-ntdef-string) or [UNICODE_STRING](/windows/win32/api/ntdef/ns-ntdef-_unicode_string) structure is passed as the argument, displays the string contained in the buffer pointed to by the `Buffer` field of the structure. Use a *size* modifier prefix of **w** to specify a `UNICODE_STRING` argument—for example, `%wZ`. The `Length` field of the structure must be set to the length, in bytes, of the string. The `MaximumLength` field of the structure must be set to the length, in bytes, of the buffer.<br /><br />Typically, the **`Z`** type character is used only in driver debugging functions that use a conversion specification, such as `dbgPrint` and `kdPrint`.|

Any of these may have been prefixed by a sign, and may have been formatted slightly differently depending on field width and precision, sometimes with unusual effects. For example, `printf("%.2f\n", INFINITY)` would print `1.#J` because the *#INF* would be "rounded" to 2 digits of precision.

|**blank** (' ')|Use a blank to prefix the output value if it's signed and positive. The blank is ignored if both the blank and + flags appear.|No blank appears.|

The width specification never causes a value to be truncated. If the number of characters in the output value is greater than the specified width, or if *width* isn't given, all characters of the value are output, subject to the *precision* specification.

|**`d`**, **`i`**, **`o`**, **`u`**, **`x`**, **`X`**|The precision specifies the minimum number of digits to be printed. If the number of digits in the argument is less than *precision*, the output value is padded on the left with zeros. The value is not truncated when the number of digits exceeds *precision*.|Default precision is 1.|

|**`s`**, **`S`**|The precision specifies the maximum number of characters to be printed. Characters in excess of *precision* aren't printed.|Characters are printed until a null character is encountered.|

In a conversion specification, the *size* field is an argument length modifier for the *type* conversion specifier. The *size* field prefixes to the *type* field—**`hh`**, **`h`**, **`j`**, **`l`** (lowercase L), **`L`**, **`ll`**, **`t`**, **`w`**, **`z`**, **`I`** (uppercase i), **`I32`**, and **`I64`**—specify the "size" of the corresponding argument—long or short, 32-bit or 64-bit, single-byte character or wide character—depending on the conversion specifier that they modify. These size prefixes are used with *type* characters in the `printf` and `wprintf` families of functions to specify the interpretation of argument sizes, as shown in the following table. The *size* field is optional for some argument types. When no size prefix is specified, the formatter consumes integer arguments—for example, signed or unsigned `char`, `short`, `int`, `long`, and enumeration types—as 32-bit `int` types, and `float`, `double`, and **`long double`** floating-point arguments are consumed as 64-bit `double` types. This behavior matches the default argument promotion rules for variable argument lists. For more information about argument promotion, see Ellipsis and Default Arguments in [Postfix expressions](../cpp/postfix-expressions.md). On both 32-bit and 64-bit systems, the conversion specification of a 64-bit integer argument must include a size prefix of **`ll`** or **`I64`**. Otherwise, the behavior of the formatter is undefined.