Most parameters and local variables have a lowercase prefix that indicates the general type of the parameter, followed by one or more words that describe the content of the parameter. The standard prefixes used in parameter and variable names are defined below:
| Prefix | Meaning |
| b | Boolean (a nonzero value means true |
| c | Character (a one-byte value) |
| dw | Long (32-bit) unsigned integer |
| f | Bit flags packed into a 16-bit integer |
| h | 16-bit handle |
| l | Long (32-bit) integer |
| lp | Long (32-bit) pointer |
| n | Short (16-bit) integer |
| p | Short (16-bit) pointer |
| pt | x- and y-coordinates packed into an unsigned 32-bit integer |
| rgb | RGB color value packed into a 32-bit integer |
| w | Short (16-bit) unsigned integer |
If no lowercase prefix is given, the parameter is a short integer whose name is descriptive.
Some examples of parameter and variable names are shown as follows:
| bIconic | ptXY | fAction |
| rgbColor | hWnd | Height |
| lpString | X | nBytes |
| Width | pMsg | Y |