define_format

Description

For active options with the data flavor, and for active and enabled options with the booldata flavor, the configuration tools will normally generate two #define's in the package's configuration header file. These take the following forms:

#define <name> <value>
#define <name>_<value>

The define_format property can be used to control exactly what appears as the value for the first of these #define's. For example, the following can be used to output some configuration data as a C string:

cdl_option <name> {
    …
    define -format="\\\"%s\\\"" <symbol>
}

The implementation of define_format involves concatenating the Tcl command format, the format string, and the string representation of the option's value, and evaluating this in a Tcl interpreter. Therefore the format string will be processed twice by a Tcl parser, and appropriate care has to be taken with quoting.

The second #define will be generated only if is a valid C preprocessor macro symbol, and is not affected by the define_format property. Also, the property is only relevant for options with the data or booldata flavor, and cannot be used in conjunction with the no_define property since it makes no sense to specify the format if no #define is generated.

Example

cdl_option CYGNUM_UITRON_VER_ID     {
    display       "OS identification"
    flavor        data
    legal_values  0 to 0xFFFF
    default_value 0
    define_format "0x%04x"
    description   "
        This value is returned in the 'id'
        field of the T_VER structure in
        response to a get_ver() system call."
}

See Also

Properties define, define_header, define_proc, if_define and no_define.