The MPE/iX intrinsics mechanism provides flexible and convenient
access to intrinsic routines from various languages. When an
external routine is designated as an intrinsic, the compiler
uses the intrinsics mechanism to determine how to invoke the routine
correctly. For example, a compiler receives information about
the number of parameters, the type of each parameter, and the
functional return type (if applicable) and does the following:
Provides a consistent intrinsic interface
Reduces the burden and error potential of coding
multiple external procedure declarations with all the parameters
and type declarations required in some languages
Ensures proper data type conversion
Verifies proper data alignment
Provides proper indirect address references to data
Generates proper reference parameter addresses
Assigns values to default parameters and correctly resolves
optional parameters omitted at the end of an intrinsic call
Provides parameter checking for languages that
have no mechanism for detailed external declarations
Permits inter-language calls that may not be possible
within a particular programming language
Provides name translation for case-insensitive languages
Allows future extension without requiring source code changes
For example, Pascal/XL requires a detailed routine header
for all external routines, and all calls to a routine must
adhere to strict typing constraints. However, by
designating a routine as an intrinsic, the compiler uses
the intrinsics mechanism to determine how to call the routine
which permits removal of the detailed routine header and
relaxes the strict typing constraints.
Since the type information, stored in the intrinsic mechanism, is in
language-independent form, you can pass parameters of
any type that conform functionally to the types expected by the
intrinsic. This allows convenient and flexible access to system
intrinsics through the intrinsics mechanism.
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 | NOTE: You can define routines for access as if they were intrinsics and
place them in new or existing intrinsic files and libraries. |
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