Define named constant

Syntax

def name value

Parameters

name - constant's name.

value - constant's value. Can be constant value of any type (number, string), or any other expression. Can include nonconstant values (global variables, functions).

Remarks

Defines a named constant. A named constant is a meaningful name that takes the place of a number, string or other expression. It is similar to a variable, but cannot be modified. It has global scope, i.e. can be used in any macro.

Often you'll find that your code contains numbers or strings that are used for certain purpose. You can improve the readability of your code, and make it easier to maintain, by using named constants instead.

Named constants also can be defined in reference files and type libraries, which allows you to use them without defining explicitly. Many definitions are in WINAPI and WINAPIV reference files. Usage example:

out WINAPI.ERROR_BAD_PATHNAME

Some Windows constants are defined by default, in the System\Declarations folder.

There are several constants defined by QM.

WINNT, WINVER, IEVER - see _winnt, _winver, _iever.

QMVER - Quick Macros version. For example, 0x2010506 is 2.1.5.6.

EXE - 1 if compiling exe, 0 if not.

QM 2.3.3. QM defines constants that are used with run-time errors. Names begin with ERR_ or ERRC_.

The ERR_ constants are defined as strings containing error code, like def ERR_INIT "581 not initialized". You can use them with end, like end ERR_INIT.
The ERRC_ constants are defined as numeric error codes, like def ERRC_INIT 581. You can use them with err, like if(_error.code=ERRC_INIT).

The error codes are in range 500-1999.

See also: declarations scope

Examples

def MAX_PATH 260
def GMEM_SHARE 0x2000
def dblconst -1.25
def strconst "String constant"
def GPTR GMEM_FIXED|GMEM_ZEROINIT
def A10 A + 10
def IID_IShellFolder uuidof("{000214E6-0000-0000-C000-000000000046}")