Building the userspace part of the flow_dissector resulted in: prog_tests/flow_dissector.c: In function ‘tx_tap’: prog_tests/flow_dissector.c:176:9: warning: implicit declaration of function ‘writev’; did you mean ‘write’? [-Wimplicit-function-declaration] return writev(fd, iov, ARRAY_SIZE(iov)); ^~~~~~ write Include <sys/uio.h> to fix this. Signed-off-by: Arthur Fabre <afabre@xxxxxxxxxxxxxx> --- tools/testing/selftests/bpf/prog_tests/flow_dissector.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c index fbd1d88a6095..c938283ac232 100644 --- a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c +++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c @@ -3,6 +3,7 @@ #include <error.h> #include <linux/if.h> #include <linux/if_tun.h> +#include <sys/uio.h> #define CHECK_FLOW_KEYS(desc, got, expected) \ CHECK_ATTR(memcmp(&got, &expected, sizeof(got)) != 0, \ -- 2.20.1