Greetings, Larry Hall (Cygwin)!
>>>> This takes 7.1 seconds on my system, with a 12-line /etc/passwd file:
>>>>
>>>> #include <pwd.h>
>>>> #include <stdio.h>
>>>> #include <stdlib.h>
>>>>
>>>> int main(int argc, const char* argv[])
>>>> {
>>>> int i;
>>>> const char* user = argv[1];
>>>>
>>>> if (!user) {
>>>> printf("usage: %s username\n", argv[0]);
>>>> exit(1);
>>>> }
>>>>
>>>> for (i = 0; i < 1000000; ++i) {
>>>> struct passwd* pw = getpwnam(user);
>>>> if (!pw) {
>>>> printf("User %s doesn't exist!\n", user);
>>>> exit(2);
>>>> }
>>>> else if (i == 0) {
>>>> printf("User %s is UID %d\n", user, pw->pw_uid);
>>>> }
>>>> }
>>>> }
>>>>
>>>> So, each getpwnam() call takes 7.1 microseconds on average.
>>>
>>> I think you forgot to put an "exit(0);" after the last printf(). Without
>>> it, you're checking for the same user a million times, which is certainly
>>> going to take a little time. ;-)
>>>
>>
>> I thought the point of the programme /was/ to call getpwnam() a million
>> times. Time this as accurately as you can. Then, with a quick division, you
>> get the time for one call.
> Hm, I missed that he summarized with _microseconds_, even though I quoted
> that too in my response. :-(
> My average was much closer to 2 microseconds per call but that could be
> machine differences.
> In any case, sorry for the noise.
In either case, repeatedly requesting the same record in a short amount of
time will only test the system level cache.
--
WBR,
Andrey Repin (anrdae...@yandex.ru) 08.02.2014, <04:39>
Sorry for my terrible english...
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