openfam::fam::fam_xor

Atomically replace a value in FAM with the Bitwise XOR of that value and some given value.

Synopsis

void fam_xor(Fam_Descriptor *descriptor, uint64_t offset, uint32_t value);

void fam_xor(Fam_Descriptor *descriptor, uint64_t offset, uint64_t value);

Description

These methods atomically replace a value in FAM with the Bitwise XOR of the value given and the existing value.

Input Arguments

Name	Description
descriptor	Descriptor associated with the data item.
Offset	Offset within the data item in FAM where value is located.
Value	Value to be combined with the existing value at the given location.

Return Values

None. Throws an exception on error.

Exceptions

Exception	Description
Fam_InvalidOption_Exception	incorrect parameters are passed.
Fam_Datapath_Exception	error occurred during atomic operation over fabric.
FAM_ERR_NOPERM	Caller does not have access rights.
FAM_ERR_LIBFABRIC	libfabric error occurred.
FAM_ERR_NOTFOUND	Item not found in the region.
FAM_ERR_GRPC	if there is a communication error with memory server
FAM_ERR_RPC_CLIENT_NOTFOUND	Memory server initialization failure

Notes

These methods atomically replace a value in FAM with the Bitwise XOR of the existing value and the value given in the method. Note that the offset argument must point to the correct value for the data type. Availability of these methods is dependent on hardware support for the operations.

A subsequent successful completion of fam_quiet() call ensures the completion of this atomic operation.

Example

#include <string.h>
#include <fam/fam.h>
#include <fam/fam_exception.h>
using namespace std;
using namespace openfam;

int main(void) {
	fam *myFam = new fam();

	// ... Initialization code here

	try {
		// look up the descriptor to a previously allocated data item
		// (an integer array with at least 10 elements)
		Fam_Descriptor *descriptor = myFam->fam_lookup("myItem", "myRegion");
	
		// Atomically replace a value of first integer element in the array
		// with the Bitwise XOR of it and a value of 0x444
		uint32_t value = 0x444;
		myFam->fam_xor(descriptor, 0, value);
	
		// ensure that the OR operation is complete
		myFam->fam_quiet();
	
		// The first integer in FAM is now bitwise XOR with a value of 0x444
	
		// ... subsequent code here
	} catch (Fam_Exception &e) {
		printf("fam API failed: %d: %s\n", e.fam_error(), e.fam_error_msg());
	}
	
	// ... Finalization code follows
}