CRTL, getenv, Description
*Conan The Librarian
In certain situations, this function attempts to perform a logical name translation on the user-specified argument: 1. If the argument to getenv does not match any of the environment strings present in your environment array, getenv attempts to translate your argument as a logical name by searching the logical name tables indicated by the LNM$FILE_ DEV logical, as is done for file processing. getenv first does a case-sensitive lookup. If that fails, it does a case-insensitive lookup. In most instances, logical names are defined in uppercase, but getenv can also find logical names that include lowercase letters. getenv does not perform iterative logical name translation. 2. If no logical name exists, getenv attempts to translate the argument string as a command-language interpreter (CLI) symbol. If it succeeds, it returns the translated symbol text. If it fails, the return value is NULL. getenv does not perform iterative CLI translation. If your CLI is the DEC/Shell, the function does not attempt a logical name translation since Shell environment symbols are implemented as DCL symbols. NOTE In OpenVMS Version 7.1, a cache of VMS environment variables (that is, logical names and DCL symbols) has been added to the getenv function to avoid the library making repeated calls to translate a logical name or to obtain the value of a DCL symbol. By default, the cache is disabled. If your application does not need to track changes in OpenVMS environment variables that can occur during its execution, the cache can be enabled by setting the DECC$ENABLE_ GETENV_CACHE logical before invoking the application (any equivalence string).