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Date:	Fri, 07 Feb 2014 22:45:02 +0000
From:	David Stacey <drstacey AT tiscali DOT co DOT uk>
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To:	cygwin AT cygwin DOT com
Subject:	Re: get rid of getpwent? (Was: cygwin-1.7.28 getpwent header declaration changes ?)
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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.

Dave.


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