ibvgetdevicelist

ibv_get_device_list is a function in the libibverbs library that is part of the InfiniBand Verbs API. It enumerates InfiniBand devices present on the local host and returns a list of pointers to ibv_device structures.

Signature and behavior: struct ibv_device **ibv_get_device_list(int *num_devices); On success, it returns a non-null pointer to an array of ibv_device pointers and writes the number of devices to *num_devices. If there are no devices, the function returns NULL and *num_devices is set to 0. On error, it returns NULL and errno is set to indicate the failure.

Usage and memory management: The caller iterates over the returned list from 0 to num_devices-1 and can obtain device information using helpers such as ibv_get_device_name(dev_list[i]). When finished, the list must be freed with ibv_free_device_list(dev_list). The memory management contract requires that the caller free the allocated list to avoid leaks.

Return value considerations: A NULL return value with num_devices > 0 generally indicates an error; a NULL return value with num_devices == 0 indicates that no InfiniBand devices were found. In both error and no-device cases, errno or the application logic should guide handling.

See also: The function is used in conjunction with other libibverbs functions such as ibv_free_device_list and ibv_get_device_name to inspect and interact with InfiniBand devices. It is part of the broader system for querying and managing RDMA hardware on a host.