get rid of getpwent? (Was: cygwin-1.7.28 getpwent header declaration changes ?)
Larry Hall (Cygwin)
reply-to-list-only-lh@cygwin.com
Fri Feb 7 21:44:00 GMT 2014
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. ;-)
--
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
More information about the Cygwin
mailing list