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HP VISUALIZE-IVL Documentation: HP 9000 Series 700 Computers > Chapter 3 Chapter 3: For Application Developers
Naming Conventions |
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Using IVL is easier if you remember some rules about the names used for functions, data types, and constants. For the purposes of writing portable code, it is also important to understand the naming conventions that are applied to extensions. In IVL, most procedure names begin with the prefix gl. (This is the naming convention for OpenGL, the "parent" of IVL.) Individual words within a procedure name begin with an uppercase letter (e.g., glDrawPixels). Similarly, most data types that are defined as part of IVL begin with the prefix GL, with subsequent letters in lower case (e.g., GLenum). Underscores are not used in procedure names nor in data type names. IVL includes pre-defined constants whose names begin with the prefix GL_ and appear as all uppercase letters, with words separated by underscores (e.g., GL_RED_BITS). Some IVL routine names begin with the prefix glX (e.g., glXMakeCurrent). This prefix indicates that the routine is specific to the X Window System environment. Applications that require portability to windowing environments other than X should isolate calls to these routines in the window system dependent portions of their code. Data types that are similarly specific to the X environment have a prefix of GLX, but follow the X convention of capitalizing the first letter of each subsequent word (e.g., GLXContext). There are a few exceptions to the rules mentioned above. Some capabilities in IVL derive from OpenGL extensions rather than the OpenGL API itself. These extensions are not currently part of the OpenGL standard. In order to encourage cooperation and similarity among vendors developing and shipping OpenGL extensions, companies have agreed to identify their proprietary extensions with a company identifier (such as HP). All new procedure names, data types, constants, and extension names will be identified with this suffix. If two or more vendors agree to implement and ship the same extension, the company identifier can be replaced with the identifier EXT. These conventions allow application developers to easily determine:
IVL includes some procedures that derive from such "common" OpenGL extensions. Several of these extensions are specific to imaging. If these extensions are added to a future revision of the OpenGL standard, the EXT suffixes will be removed. IVL also contains a few procedures and constants that are specific to HP. The procedure names in this category contain the suffix HP and the constant names contain the suffix _HP. Hewlett-Packard has kept the number of proprietary procedures and constants to a minimum, but there are requirements to provide certain critical features that aren't defined by the OpenGL standard or any existing OpenGL extension. HP has offered these extensions to the OpenGL community and is encouraging other vendors to implement them. If any other vendor agrees to support them, the suffixes may change from HP to EXT. Furthermore, if the OpenGL Architecture Review Board integrates the HP extensions into a future version of the OpenGL standard, then the suffixes will be eliminated. Some procedures in IVL come in several variations, differing only in the data type of the arguments they accept. The key to understanding the difference in the routines is to look at the last few letters of the name (prior to any extension suffix like EXT or HP). The table below summarizes the combinations of letters that may appear at the end of procedure names:
The following table summarizes the naming convention used with IVL routines:
The following table summarizes the naming convention used with IVL data types:
Note: IVL does not include any data-type extensions. The following table summarizes the naming convention used with IVL constants:
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