gettimeofday is not monotonic. It would give wrong results in some situation like leap seconds, when switching between daylight saving time and non-DST, NTP changes the time or when the administrator of the system changes it manually. The function is also obsolete since POSIX.1-2008.
clock_gettime is recommended to get a monotonic timesource and as general replacement of gettimeofday. Signed-off-by: Sven Eckelmann <[email protected]> --- Makefile | 2 +- functions.c | 17 +++++++++-------- 2 files changed, 10 insertions(+), 9 deletions(-) diff --git a/Makefile b/Makefile index e980587..57d9a4e 100755 --- a/Makefile +++ b/Makefile @@ -46,7 +46,7 @@ MANPAGE = man/batctl.8 # batctl flags and options CFLAGS += -Wall -W -std=gnu99 -fno-strict-aliasing -MD -MP CPPFLAGS += -D_GNU_SOURCE -LDLIBS += -lm +LDLIBS += -lm -lrt # disable verbose output ifneq ($(findstring $(MAKEFLAGS),s),s) diff --git a/functions.c b/functions.c index f9feca4..bc4f9f8 100644 --- a/functions.c +++ b/functions.c @@ -48,6 +48,7 @@ #include <netlink/handlers.h> #include <netlink/msg.h> #include <netlink/attr.h> +#include <time.h> #include "main.h" #include "functions.h" @@ -59,7 +60,7 @@ #define PATH_BUFF_LEN 200 -static struct timeval start_time; +static struct timespec start_time; static char *host_name; char *line_ptr = NULL; @@ -80,23 +81,23 @@ const char *fs_compile_out_param[] = { void start_timer(void) { - gettimeofday(&start_time, NULL); + clock_gettime(CLOCK_MONOTONIC, &start_time); } double end_timer(void) { - struct timeval end_time, diff; + struct timespec end_time, diff; - gettimeofday(&end_time, NULL); + clock_gettime(CLOCK_MONOTONIC, &end_time); diff.tv_sec = end_time.tv_sec - start_time.tv_sec; - diff.tv_usec = end_time.tv_usec - start_time.tv_usec; + diff.tv_nsec = end_time.tv_nsec - start_time.tv_nsec; - if (diff.tv_usec < 0) { + if (diff.tv_nsec < 0) { diff.tv_sec--; - diff.tv_usec += 1000000; + diff.tv_nsec += 1000000000; } - return (((double)diff.tv_sec * 1000) + ((double)diff.tv_usec / 1000)); + return (((double)diff.tv_sec * 1000) + ((double)diff.tv_nsec / 1000000)); } char *ether_ntoa_long(const struct ether_addr *addr) -- 2.8.1
