sizeof

     sizeof(double)

would return 8. The sizeof operator can also compute the size of simple structs or unions (see Structs and Unions). A simple struct is one that does not contain if statements or other statements that may change its size when declared. Attempting to compute the size of a non-simple struct or union will generate an error.

The special keyword startof can be used on a variable that has been declared in a Template to calculate the starting address of the bytes the variable is mapped to in the file. The address is returned in local coordinates. For example, after opening a BMP file, use the following command in a script to position the cursor/caret at the beginning of the first line of bitmap data:

     SetCursorPos( startof( lines[0] ) ); 

exists

The special exists operator can be used to determine if a variable has been declared. The operator will return 1 if the given variable exists, or 0 if it does not. For example, after opening a ZIP file, the following command in a script will output all file names:

     int i;
     string s;
     while( exists( file[i] ) )
     {
         s = file[i].frFileName;
         Printf( "%s\n", s );
         i++;
     } 

function_exists

The function_exists operator can be used to test if a particular function is defined either as a user-defined function or a built-in function (see Functions for more information). The operator returns 1 if the function exists or 0 if it does not. For example:

     if( function_exists(CopyStringToClipboard) )
     {
        ...
     }

this

The this keyword can be used to access the variable representing the current structure being defined (see Structs and Unions). For example:

      void PrintHeader( struct HEADER &h )
      {
          Printf( "ID1 = %d\n", h.id1 );
          Printf( "ID2 = %d\n", h.id2 );
      }
      
      struct HEADER
      {
          int id1; 
          int id2; 
          PrintHeader( this );
      } h1;

If no current structure is currently being defined, this is NULL.

parentof

The parentof keyword can be used to access the struct or union that contains a given variable. For example:

      void PrintHeader( struct HEADER &h )
      {
          Printf( "ID1 = %d\n", h.id1 );
          Printf( "ID2 = %d\n", h.id2 );
      }
      
      struct HEADER
      {
          int id1; 
          int id2; 
          
          struct SUBITEM
          {
              int data1;
              int data2;
              PrintHeader( parentof(this) );
          } item1; 
      
          PrintHeader( parentof(item1) );
      
      } h1; 

If the given variable is not inside a struct or union an error will be generated.