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"RawPointer" (Compiled Type)

"RawPointer"::[t]

represents a pointer to an object with type t, suitable for use with external libraries.

Details

  • "RawPointer"::[t] is equivalent to t* in C.

Constructors

  • ToRawPointer can be used to create a pointer object that uses memory allocated on the stack and is valid until the enclosing function returns.
  • Unless wrapped with "Managed", pointer objects constructed with CreateTypeInstance are not automatically memory managed and must be manually freed with DeleteObject.
  • CreateTypeInstance["RawPointer"::[type]] constructs a raw pointer.
  • CreateTypeInstance["Managed"::["RawPointer"::[type]]] constructs a memory-manged C raw pointer.

Properties

  • Information[ptr,"BaseType"] for ptr of type "RawPointer"::[t] gives "TypeSpecifier"::[t].
  • FromRawPointer[ptr] returns the value pointed to by ptr.

Conversions

    From Expressions

  • RawPointer expressions can be converted into raw pointer types in compiled code.

    • To Expressions

  • "RawPointer" compiled elements can be converted into RawPointer expressions. Note that the raw pointer in compiled code must be allocated dynamically with CreateTypeInstance.

    • "CArray"

  • Cast can be used to bitcast pointers to and from C arrays.

    • "OpaqueRawPointer"

  • Cast can be used to bitcast pointers to and from opaque pointers.

Run-Time Errors

  • Dereferencing a pointer with FromRawPointer is an unsafe operation. Attempting to dereference an invalid pointer can lead to a crash.

Examples

Basic Examples  (4)

Create a "RawPointer"::["MachineInteger"], then dereference it:

Represent a library function that returns its results by modifying a pointer:

Compile a program that uses the function:

Compile a program that returns a raw pointer containing a value:

A compiled function that accepts the raw pointer, extracts the value and deletes the pointer:

Compile a program that returns a managed raw pointer containing a value:

Call the compiled code:

A compiled function that accepts the managed raw pointer and extracts the value:

The pointer should not be manually freed, since that is done automatically by "Managed":