"Converts" to a boolean value a given expression or value of other type
Implemented by: FreeBASIC, Gambas
With variations:
Also written as:
As part of a number of type conversion functions, CBOOL more precisely evaluates a value or expression to a true or false value.
bVar = CBOOL(arg)
The BASICs that implement it, though, perform the evaluation differently.
In Gambas, CBOOL will return boolean false if:
FreeBASIC's CBOOL will also return true for a numeric expression or value different than 0, but for strings it will return a boolean true only if the argument is the proper string "true" in any capitalization:
PRINT CBOOL(0) 'false PRINT CBOOL(-1) 'true PRINT CBOOL(1) 'true PRINT CBOOL("") 'false PRINT CBOOL("truth") 'false PRINT CBOOL("false") 'false PRINT CBOOL("TrUe") 'true
It might be worth noting, even if it does not conflict with the results of CBOOL in known implementations, that the -1 numeric value is used for representing the boolean true value in some older BASICs.