SYNOPSIS

#include <sys/uio.h> #include <corosync/evs.h>

int evs_mcast_groups(evs_handle_t handle, evs_guraantee_t guarantee, evs_group_t *groups, int group_entries, struct iovec *iovec, int iov_len);

DESCRIPTION

The evs_mcast_groups(3) function multicasts a message to all the groups specified in the arguemnt groups. Messages are delivered to all processors in the system that are described by the current configuration.

The argument handle describes a handle created with evs_initialize(3).

The argument guarantee requests a delivery guarantee for the message to be sent. The evs_guarantee_t type is defined by:

typedef enum {
    EVS_TYPE_UNORDERED,       /* not implemented */
    EVS_TYPE_FIFO,          /* same as agreed */
    EVS_TYPE_AGREED,          /* implemented */
    EVS_TYPE_SAFE           /* not implemented */
} evs_guarantee_t;

The meanings of the evs_guarantee_t typedef are:

EVS_GUARANTEE_UNORDERED

Messages are guaranteed to be delivered, but with no particular order. This mode is unimplemented in the EVS library.

EVS_GUARANTEE_FIFO

Messages are guaranteed to be delivered in first sent first delivery order from one one. In fact, this guarantee is actually the AGREED guarantee.

EVS_GUARANTEE_AGREED

All processors must agree on the order of delivery. If a message is sent from two or more processors at about the same time, the delivery will occur in the same order to all processors.

EVS_GUARANTEE_SAFE

All processors must agree on the order of delivery. Further all processors must have a copy of the message before any delivery takes place. This mode is unimplemented in the EVS library.

The groups argument is of the type evs_group_t which is defined by the structure:

typedef struct {
    char key[32];
} evs_groups_t;

The group_entries argument describes the number of entries in the group argument.

The iovec argument describes the scatter/gather list which is used to transmit a message. This is a standard socket structure described by:

struct iovec
{
    void *iov_base;     /* Pointer to data.  */
    unsigned int iov_len;     /* Length of data.  */
};

The iovlen argument describes the number of entires in the iovec argument.

RETURN VALUE

This call returns the EVS_OK value if successful, otherwise an error is returned.