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How can I obtain an array with uid and names?

I could iterate from 0 to 99999 and do a getpwnam(). However most machines have less than 5 accounts, so it's not optimal. I don't know what framework is responsible for this and thus I have no clue what to search for.

Is there a more optimal solution that can traverse the accounts?

Edit: Right after I posted I discovered getpwent() for traversing accounts.

setpwent();
struct passwd *pw;
while ((pw = getpwent())) printf("%d\n", pw->pw_uid);
endpwent();

However that doesn't indicate wether an account is a System Preferences account or not.

So still how does one obtain the System Preferences accounts?

Edit: I have found the commandline equivalent of this, the dscl command.

prompt> dscl . -list /Users UniqueID
_mysql                  74
_postfix                27
_spotlight              89
_sshd                   75
_windowserver           88
_www                    70
daemon                  1
johndoe                 501
nobody                  -2
root                    0
neoneye
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1 Answers1

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Use getgrnam("staff") to get a group record for the staff group. The gr_mem member, while not explained in detail by the manpage, appears to be an array of user names terminated by a NULL pointer.

To find which users are administrators, do the same thing with the admin group.

Peter Hosey
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  • Hmm, I have 4 accounts (simon,neoneye,johndoe,testuser1), but two of them aren't listed in the staff group, even though they are in the staff group. What I'm seeing is STAFF: root, ADMIN: root, ADMIN: neoneye, ADMIN: simon I don't see my johndoe anywhere nor my testuser1. Perhaps theres is more to it? if(gr = getgrnam("staff")) { for (i=0; gr->gr_mem[i]!=0; ++i) { NSLog(@"STAFF: %s",gr->gr_mem[i]); } – neoneye Jun 06 '10 at 09:55
  • neoneye: I see that you've accepted this answer. I take it you got it working, then? What was wrong? – Peter Hosey Jun 06 '10 at 20:38
  • sorry, I accepted it, but unfortunately getgrnam("staff") doesn't seem to list all the accounts on my system, so I guess I have to look for another solution. iirc there was some user account info in the SystemConfiguration api. – neoneye Jun 06 '10 at 22:32