Comments within a SOM IDL file

SOM IDL supports both C and C++ comment styles. The characters "//" start a line comment, which finishes at the end of the current line. The characters "/*" start a block comment that finishes with the "*/". Block comments do not nest. The two comment styles can be used interchangeably.

Comments in a SOM IDL specification must be strictly associated with particular syntactic elements, so that the SOM Compiler can put them at the appropriate place in the header and implementation files it generates. Therefore, comments may appear only in these locations (in general, following the syntactic unit being commented):

• At the beginning of the IDL specification

• After a semicolon

• Before or after the opening brace of a module, interface statement, implementation statement, structure definition, or union definition

• After a comma that separates parameter declarations or enumeration members

• After the last parameter in a prototype (before the closing parenthesis)

• After the last enumeration name in an enumeration definition (before the closing brace)

• After the colon following a case label of a union definition

• After the closing brace of an interface statement

Numerous examples of the use of comments can be found in the Tutorial of Chapter 2.

Because comments appearing in a SOM IDL specification are transferred to the files that the SOM Compiler generates, and because these files are often used as input to a programming language compiler, it is best within the body of comments to avoid using characters that are not generally allowed in comments of most programming languages. For example, the C language does not allow "*/" to occur within a comment, so its use is to be avoided, even when using C++ style comments in the .idl file.

SOM IDL also supports throw-away comments. They may appear anywhere in an IDL specification, because they are ignored by the SOM Compiler and are not transferred to any file it generates. Throw-away comments start with the string "//#" and end at the end of the line. Throw-away comments can be used to "comment out" portions of an IDL specification.

To disable comment processing (that is, to prevent the SOM Compiler from transferring comments from the IDL specification to the binding files it generates), use the -c option of the sc or somc command when running the SOM Compiler (See Section 4.3, "The SOM Compiler"). When comment processing is disabled, comment placement is not restricted and comments can appear anywhere in the IDL specification.