BIO_FLAGS_SHOULD_RETRY
BIO_set_flags(b, (BIO_FLAGS_IO_SPECIAL|BIO_FLAGS_SHOULD_RETRY))
BIO_set_flags(b, (BIO_FLAGS_READ|BIO_FLAGS_SHOULD_RETRY))
BIO_set_flags(b, (BIO_FLAGS_WRITE|BIO_FLAGS_SHOULD_RETRY))
BIO_clear_flags(b, (BIO_FLAGS_RWS|BIO_FLAGS_SHOULD_RETRY))
BIO_test_flags(b, (BIO_FLAGS_RWS|BIO_FLAGS_SHOULD_RETRY))
#define BIO_should_retry(a) BIO_test_flags(a, BIO_FLAGS_SHOULD_RETRY)
BIO_FLAGS_READ|BIO_FLAGS_SHOULD_RETRY);
BIO_FLAGS_WRITE|BIO_FLAGS_SHOULD_RETRY);
BIO_FLAGS_IO_SPECIAL|BIO_FLAGS_SHOULD_RETRY);