On 2014-02-12 12:13, Daniel Gollub wrote:
This makes life easier for plugins written in C++ since they do not need to deal with struct initilization issues with the ioengine_ops symbol.With g++ a non-static ioengine_ops in global scope like this: struct ioengine_ops ioengine = { .name = "null", .version = FIO_IOOPS_VERSION, .queue = fio_null_queue, .commit = fio_null_commit, }; Results in: cpp_null2.cc: At global scope: cpp_null2.cc:112:1: error: C99 designator ‘name’ outside aggregate initializer cpp_null2.cc:112:1: sorry, unimplemented: non-trivial designated initializers not supported cpp_null2.cc:112:1: sorry, unimplemented: non-trivial designated initializers not supported cpp_null2.cc:112:1: sorry, unimplemented: non-trivial designated initializers not supported cpp_null2.cc:112:1: sorry, unimplemented: non-trivial designated initializers not supported $ Example get_iongine() symbol usage: ---8<--- extern "C" { void get_ioengine(struct ioengine_ops **ioengine_ptr) { struct ioengine_ops *ioengine; *ioengine_ptr = (struct ioengine_ops *) malloc(sizeof(struct ioengine_ops)); ioengine = *ioengine_ptr; strcpy(ioengine->name, "cpp_null"); ioengine->version = FIO_IOOPS_VERSION; ioengine->queue = fio_null_queue; ioengine->commit = fio_null_commit; ioengine->getevents = fio_null_getevents; ioengine->event = fio_null_event; ioengine->init = fio_null_init; ioengine->cleanup = fio_null_cleanup; ioengine->open_file = fio_null_open; ioengine->flags = FIO_DISKLESSIO; } } --->8--- Signed-off-by: Daniel Gollub <[email protected]> --- ioengines.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/ioengines.c b/ioengines.c index d71e372..c080da3 100644 --- a/ioengines.c +++ b/ioengines.c @@ -90,6 +90,7 @@ static struct ioengine_ops *dlopen_ioengine(struct thread_data *td, { struct ioengine_ops *ops; void *dlhandle; + typedef void (*get_ioengine_t)(struct ioengine_ops **); dprint(FD_IO, "dload engine %s\n", engine_lib); @@ -107,6 +108,19 @@ static struct ioengine_ops *dlopen_ioengine(struct thread_data *td, ops = dlsym(dlhandle, engine_lib); if (!ops) ops = dlsym(dlhandle, "ioengine"); + + /* + * For some external engines (like C++ ones) it is not that trivial + * to provide a non-static ionengine structure that we can reference. + * Instead we call a method which allocates the required ioengine + * structure. + */ + if (!ops) { + get_ioengine_t get_ioengine = dlsym(dlhandle, "get_ioengine"); + if (get_ioengine) + get_ioengine(&ops); + } + if (!ops) { td_vmsg(td, -1, dlerror(), "dlsym"); dlclose(dlhandle);
This looks fine, but lets put that typedef in ioengine.h instead. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
