How to Read the Syntax Diagrams

• Read the syntax diagrams from left to right, from top to bottom, following the path of the line.

  The >>--- symbol indicates the beginning of a command, directive, or statement.

  The ---> symbol indicates that the command, directive, or statement syntax is continued on the next line.

  The >--- symbol indicates that a command, directive, or statement is continued from the previous line.

  The --->< symbol indicates the end of a command, directive, or statement.

  Diagrams of syntactical units other than complete commands, directives, or statements start with the >--- symbol and end with the ---> symbol.

  Note:

  In the following diagrams, statement represents a C or C++ command, directive, or statement.
• Required items appear on the horizontal line (the main path).

  >>-statement--required_item------------------------------------><
   
  

• Optional items appear below the main path.

  >>-statement--+---------------+--------------------------------><
                '-optional_item-'
   
  

• If you can choose from two or more items, they appear vertically, in a stack.

  If you must choose one of the items, one item of the stack appears on the main path.

  >>-statement--+-required_choice1-+-----------------------------><
                '-required_choice2-'
   
  

  If choosing one of the items is optional, the entire stack appears below the main path.

  >>-statement--+------------------+-----------------------------><
                +-optional_choice1-+
                '-optional_choice2-'
   
  

  The item that is the default appears above the main path.

                .-default_item---.
  >>-statement--+-alternate_item-+-------------------------------><
   
  

• An arrow returning to the left above the main line indicates an item that can be repeated.

                .-----------------.
                V                 |
  >>-statement----repeatable_item-+------------------------------><
   
  

  A repeat arrow above a stack indicates that you can make more than one choice from the stacked items, or repeat a single choice.

• Keywords appear in nonitalic letters and should be entered exactly as shown (for example, extern).

  Variables appear in italicized lowercase letters (for example, identifier). They represent user-supplied names or values.

• If punctuation marks, parentheses, arithmetic operators, or other such symbols are shown, you must enter them as part of the syntax.

The following syntax diagram example shows the syntax for the #pragma comment directive. See Pragma directives for information on the #pragma directive.

 1   2    3    4         5         6                               9     10 
 >>--#--pragma--comment--(-------compiler---------------------------)----><
                          |                                     |
                          +-----date----------------------------+
                          |                                     |
                          +-----timestamp-----------------------+
                          |                                     |
                          +-----copyright-----------------------+
                             |             |  |                 |
                             +--user-------+  +--,-"characters"-+

                                                 7       8 

•  1  This is the start of the syntax diagram.
•  2  The symbol # must appear first.
•  3  The keyword pragma must appear following the # symbol.
•  4  The name of the pragma comment must appear following the keyword pragma.
•  5  An opening parenthesis must be present.
•  6  The comment type must be entered only as one of the types indicated: compiler, date, timestamp, copyright, or user.
•  7  A comma must appear between the comment type copyright or user, and an optional character string.
•  8  A character string must follow the comma. The character string must be enclosed in double quotation marks.
•  9  A closing parenthesis is required.
•  10  This is the end of the syntax diagram.

The following examples of the #pragma comment directive are syntactically correct according to the diagram shown above:

   #pragma comment(date)
   #pragma comment(user)
   #pragma comment(copyright,"This text will appear in the module")