generic

Generic Address Space.

__generic (unnamed address space)

Notes

The following rules apply when using pointers that point to the generic address space:

  • A pointer that points to the global, local or private address space can be implicitly converted to a pointer to the unnamed generic address space but not vice-versa.

  • Pointer casts can be used to cast a pointer that points to the global, local or private space to the unnamed generic addresss space and vice-versa.

  • A pointer that points to the constant address space cannot be cast or implicitly converted to the generic address space.

Example

This is the canonical example. In this example, function foo() is declared with an argument that is a pointer with no address space qualifier.

void foo(int *a) { *a = *a + 2; } kernel void k1(local int *a) { … foo(a); … } kernel void k2(global int *a) { … foo(a); … }

In the example below, var is in the unnamed generic address space which gets mapped to the global or local address space depending on the result of the conditional expression.

kernel void bar(global int *g, local int *l) { int *var; if (is_even(get_global_id(0)) var = g; else var = l; *var = 42; … }

The example below is an example with one unnamed generic address space pointer with multiple named address space assignments.

int *ptr; global int g; ptr = &g; // legal local int l; ptr = &l; // legal private int p; ptr = &p; // legal constant int c; ptr = &c; // illegal

The example below is an example with one unnamed generic address space pointer being assigned to point to several named address spaces.

global int * gp; local int *lp; private int *pp; int *p; p = gp; // legal p = lp; // legal p = pp; // legal // it is illegal to convert from a generic pointer // to an explicit address space pointer without a cast: gp = p; // compile-time error lp = p; // compile-time error pp = p; // compile-time error

Specification

OpenCL Specification

Also see

__global, __constant, __private, qualifiers

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