Applying the target Attribute to Multiple Declarations

When you have several data and function declarations, rather than specifying each declaration with its own target attribute. you can enclose a group of data and function declarations between the push and pop variants of the offload_attribute pragma.

When offloaded code makes use of declarations from C standard headers, Intel® Threading Building Blocks (Intel® TBB), Intel® Cilk™ Plus, or user-written #include declarations, you must enclose those declarations within the offload_attribute pragma, with a specified target-name corresponding to the offload model under which the declarations are used.

Enclose the calls to the include files when offloading using a pragma as follows:

#pragma offload_attribute(push, target(mic))
...
#pragma offload_attribute(pop) 

Enclose the calls to the include files when offloading using shared virtual memory as follows:

#pragma offload_attribute(push, _Cilk_shared)
...
#pragma offload_attribute(pop)

You can only use functions and data under a single offload model within your program, so any include file you call can only be marked for use under a single offload model. Consequently, you cannot use the keyword _Cilk_offload with any include file enclosed between #pragma offload_attribute(push, target(mic)) and #pragma offload_attribute(pop).

Conversely, you cannot use the the #pragma offload statement with any include file enclosed between #pragma offload_attribute(push, _Cilk_shared) and #pragma offload_attribute(pop)

Example

The functions function_1 and function_2 each need the target attribute, as do all the declarations within some include files. It is convenient to put the offload_attribute pragma around all those declarations.

#pragma offload_attribute(push,target(mic))
#include <stdio.h>
#include <math.h>

void function_1();
void function_2();
#pragma offload_attribute(pop)


int main()
{
	#pragma offload target(mic)
	{
		function_1();
		printf("...");
	}
	...
	#pragma offload target(mic)
	function_2();
	...
}