On 2018-11-08 17:17, Simon Marchi wrote:
On 2018-11-08 17:08, Jonathan Rajotte wrote:
The nanoseconds part of the timespec struct time_a is not always
bigger than time_b since it wrap around each seconds.
Use the absolute value of the nanosecond difference to perform
unsigned long operation.
Signed-off-by: Jonathan Rajotte <jonathan.rajotte-jul...@efficios.com>
---
src/common/sessiond-comm/inet.c | 2 +-
src/common/sessiond-comm/inet6.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/common/sessiond-comm/inet.c
b/src/common/sessiond-comm/inet.c
index e0b3e7a96..cb6f45357 100644
--- a/src/common/sessiond-comm/inet.c
+++ b/src/common/sessiond-comm/inet.c
@@ -124,7 +124,7 @@ unsigned long time_diff_ms(struct timespec
*time_a,
unsigned long result_ms;
sec_diff = time_a->tv_sec - time_b->tv_sec;
- nsec_diff = time_a->tv_nsec - time_b->tv_nsec;
+ nsec_diff = labs(time_a->tv_nsec - time_b->tv_nsec);
result_ms = sec_diff * MSEC_PER_SEC;
result_ms += nsec_diff / NSEC_PER_MSEC;
diff --git a/src/common/sessiond-comm/inet6.c
b/src/common/sessiond-comm/inet6.c
index dfb5fc5d1..b73802d48 100644
--- a/src/common/sessiond-comm/inet6.c
+++ b/src/common/sessiond-comm/inet6.c
@@ -122,7 +122,7 @@ unsigned long time_diff_ms(struct timespec
*time_a,
unsigned long result_ms;
sec_diff = time_a->tv_sec - time_b->tv_sec;
- nsec_diff = time_a->tv_nsec - time_b->tv_nsec;
+ nsec_diff = labs(time_a->tv_nsec - time_b->tv_nsec);
result_ms = sec_diff * MSEC_PER_SEC;
result_ms += nsec_diff / NSEC_PER_MSEC;
That doesn't look right either. With
time_a = 2.9 s
time_b = 3.1 s
it will result in
sec_diff = 1 s
nsec_diff = 0.8 s
Added, the result will be 1.8 seconds, when actually we expect 0.2 s.
You probably have no choice but do the "borrowing" by hand, like we
did when learning subtraction in elementary school :). Maybe this
deserves some unit tests, since it's apparently easy to get it wrong.
Actually, see here for an example:
https://www.gnu.org/software/libc/manual/html_node/Elapsed-Time.html
Simon
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