CentOS 7.0 - man page for ibv_open_qp (centos section 3)

IBV_OPEN_QP(3)			  Libibverbs Programmer's Manual		   IBV_OPEN_QP(3)

NAME
       ibv_open_qp - open a shareable queue pair (QP)

SYNOPSIS
       #include <infiniband/verbs.h>

       struct ibv_qp *ibv_open_qp(struct ibv_context *context,
				  struct ibv_qp_open_attr *qp_open_attr);

DESCRIPTION
       ibv_open_qp()  opens  an  existing queue pair (QP) associated with the extended protection
       domain xrcd.  The argument qp_open_attr is  an  ibv_qp_open_attr  struct,  as  defined  in
       <infiniband/verbs.h>.

       struct ibv_qp_open_attr {
	       uint32_t 	 comp_mask;  /* Identifies valid fields */
	       uint32_t 	 qp_num;     /* QP number */
	       struct		 *ibv_xrcd;  /* XRC domain */
	       void		*qp_context; /* User defined opaque value */
	       enum ibv_qp_type  qp_type;    /* QP transport service type */

       ibv_destroy_qp()  closes  the  opened QP and destroys the underlying QP if it has no other
       references.  qp.

RETURN VALUE
       ibv_open_qp() returns a pointer to the opened QP, or NULL if the request fails.	Check the
       QP number (qp_num) in the returned QP.

NOTES
       ibv_open_qp()  will fail if a it is asked to open a QP that does not exist within the xrcd
       with the specified qp_num and qp_type.

SEE ALSO
       ibv_alloc_pd(3), ibv_create_qp(3), ibv_create_qp_ex(3), ibv_modify_qp(3), ibv_query_qp(3)

AUTHORS
       Sean Hefty <sean.hefty@intel.com>

libibverbs				    2011-08-12				   IBV_OPEN_QP(3)