◄Up► ◄Contents► ◄Index► ◄Back►
─────PWB Extensions─────────────────────────────────────────────────────────
 
     All extension functions exported to PWB must have the same
     prototype. The first argument (CMDDATA) should be ignored; it is
     present for historical reasons. The second argument (ARG *pArg) is
     a pointer to an argument structure. The third argument (flagType
     fMeta) is a Boolean value that specifies if the Meta state is
     turned on or off.
 
     The ARG structure contains data about the arguments the user gave
     when executing the function. It is defined in EXT.H as follows:
 
         struct PWBargType {
             int   argType;                      //Discriminant
             union {
                 struct noargType     noarg;     //No arguments
                 struct textargType   textarg;   //Text argument
                 struct nullargType   nullarg;   //Arg count only
                 struct lineargType   linearg;   //Line
                 struct streamargType streamarg; //Stream
                 struct boxargType    boxarg;    //Box
             } arg;
             PWND  pwnd;
             PINS  pins;
             PFILE pfile;
             };
         typedef struct PWBargType ARG;
 
     The argType member specifies which argument is active in the arg
     union.
 
     The possible argType values for each function are defined by the
     argType member of the cmdDesc structure in the function's cmdTable
     entry. Incompatible arguments are intercepted and refused by PWB.
     PWB does not call the extension function when an incompatibale
     argument is given.
     See: ◄Extension Command Table►
          ◄Extension Argument Types►
 
     The following arg structures can be passed to extension functions:
 
     argType     Description
 
     noarg       No argument or selection
     nullarg     PWB Arg function executed, but no selection made and no
                 text typed in the Text Argument dialog box.
     textarg     Text argument
     linearg     Lines selected
     streamarg   Stream selected
     boxarg      Box selected
 
     See: ◄Extension Argument Structure►
                                    -♦-