Article #20874: Why can't I use the streaming operators with the VCL classes Set, Variant, and Currency?

Question: When I use operator << with a class derived from Set, such as TFontStyles, I get the compiler error "operator << not implemented in type < stream type > for arguments of type TFontStyle" Why can't I use the streaming operators with the VCL classes Set, Variant, and Currency? Answer: You need to define a preprocessor directive enabling this functionality. Place the following line above the include directive for vcl.h: #define VCL_IOSTREAM Or you can add VCL_IOSTREAM to the project conditional defines under Project|Options|Directories/Conditionals

Last Modified: 13-MAR-02