The following are atomic labels, or labels that refer to primitive data types. Where available, the equivalent Microsoft C data type is also listed.
| Label | Meaning | MS C Type |
| <CHAR> | 8-bit signed integer | signed char | |
| <BYTE> | 8-bit unsigned quantity | unsigned char | |
| <INT> | 16-bit signed integer in Intel format | signed int | |
| <WORD> | 16-bit unsigned quantity in Intel format | unsigned int | |
| <LONG> | 32-bit signed integer in Intel format | signed long | |
| <DWORD> | 32-bit unsigned quantity in Intel format | unsigned long | |
| <FLOAT> | 32-bit IEEE floating point number | float | |
| <DOUBLE> | 64-bit IEEE floating point number | double | |
| <STR> | String (a sequence of characters), | ||
| <ZSTR> | NULL-terminated string, | ||
| <BSTR> | String with byte (8-bit) size prefix, | ||
| <WSTR> | String with word (16-bit) size prefix, | ||
| <BZSTR> | NULL-terminated string with byte size prefix, | ||
| <WZSTR> | NULL-terminated string with word size prefix, | ||
NULL-terminated means that the string is followed by a character with ASCII value 0.
A size prefix is an unsigned integer, stored as a byte or a word in Intel format, that specifies the length of the string. In the case of strings with BZ or WZ modifiers, the size prefix specifies the size of the string without the terminating NULL.
Note:
The WINDOWS.H header file defines the C types BYTE, WORD, LONG, and DWORD. These types correspond to labels <BYTE>, <WORD>, <LONG>, and <DWORD>, respectively.