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On 2/7/2014 5:45 PM, David Stacey wrote:
On 07/02/14 21:44, Larry Hall (Cygwin) wrote:On 2/7/2014 3:09 PM, Warren Young wrote: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. -- Larry _____________________________________________________________________ A: Yes. > Q: Are you sure? >> A: Because it reverses the logical flow of conversation. >>> Q: Why is top posting annoying in email? -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
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