Predefined Conditionals

Predefined conditionals are symbols available in DataFlex to help control conditionally compiled code in the current workspace.

Other than Is$Windows and Is$WebApp, all other symbols that control #IFDEF conditionally compiled code must be configured and managed in the Configure Workspace dialog on the Conditionals tab.

Conditional	Purpose
`Is$Windows`	The Studio's parser assumes that the `Is$Windows` special symbol is predefined. This means that you do not need to specify this symbol for any workspace.
`Is$WebApp`	The Studio will automatically manage the True/False value of this symbol for you according to whether the current project you are working on is a Web Application project.
`IS$WIN64`	When code or settings must only be applied to the 64-bit environment, not 32-bit, the compiler switch `IS$WIN64` may be used. `#IFDEF IS$WIN64` `#Replace LONGPTR_DTSIZE 8` `#ELSE` `#Replace LONGPTR_DTSIZE 4` `#ENDIF` In 32-bit, both `DWord` and `Handle` are 32-bit items (4 bytes), which does not lead to any padding. However, in 64-bit, `Handle` has become 64-bit (8 bytes) and that causes the struct to have 8-byte alignment, which means that in Windows compilers there will be 4 bytes of space inserted after `lStructSize`. If this doesn't get corrected in 64-bit environments, there can be an unexpected runtime error or crash upon calling the external function. The solution in DataFlex code is: `Struct tWinChooseFont` `DWord lStructSize` `#IFDEF IS$WIN64` `Integer iStructAlignment` `#ENDIF` `Handle hwndOwner` `End_Struct`
`COMP$TIMESTAMP`	Globally available in your programs. `COMP$TIMESTAMP` is defined as the UNIX UTC (number of seconds since 1 January 1970; locale independent) timestamp as a constant `UBigInt`. While custom calculations are possible, the Date & Time library is available to have calculations easily performed. `Move COMP$TIMESTAMP to ullUnixUTC`

Predefined Conditionals

See Also