[Home] [Downloads] [Search] [Help/forum]

Gammon Software Solutions forum

See www.mushclient.com/spam for dealing with forum spam. Please read the MUSHclient FAQ!

[Folder]  Entire forum
-> [Folder]  SMAUG
. -> [Folder]  SMAUG coding
. . -> [Subject]  'buf' shadows a global declaration
Home  |  Users  |  Search  |  FAQ
Username:
Register forum user name
Password:
Forgotten password?
'buf' shadows a global declaration

[Reply to this subject]  Reply to this subject   [New subject]  Start a new subject   [Refresh] Refresh page

Posted by Miked   USA  (30 posts)  [Biography] bio
Date Wed 13 Jul 2005 10:07 AM (UTC)  [ quote  ]
Message
I get an error saying that 'buf' shadows a global declaration, but I go to take it out and I get more errors. For example, I take it out of do_who in act_info.c of SWFotE 1.2, and I get errors in passing stuff from incompatable pointer type. Any suggestions, or do you need more info?
[Go to top] top
Posted by Robert Powell   Australia  (349 posts)  [Biography] bio
Date Reply #1 on Wed 13 Jul 2005 10:48 AM (UTC)  [ quote  ]
Message
As long as you take out the shadowed declaration all should be fine.

void do_nothing(*argument)
char declare[MIL]

if (something and something)
  char declare[MIL] //remove this one


Well my example might not be very pretty or very acurate, but you should remove where the variable has been declared for the second time within that function.

Now, there are other more sinister shaddowed declarations, ones that deal with librarys and such, some more detail would be needed to see what exaclty you have going on.
EldhaMUD Game Developments
The_Fury: Lead Developer, Head Coder
http://fury.eldhamud2.org
[Go to top] top
Posted by Greven   Canada  (835 posts)  [Biography] bio
Date Reply #2 on Wed 13 Jul 2005 02:15 PM (UTC)  [ quote  ]
Message
This issue generally means that you have a variable called "buf" declared somewhere as a global variable(usually) and that the compiler is complaining because it is not obvious which one to use inside the function: the local one, or the global one. Since "buf" is very common as a local variable, I wouls likely change the global one.
Nobody ever expects the spanish inquisition!

darkwarriors.net:4848
http://darkwarriors.net
[Go to top] top
Posted by Zeno   USA  (2,867 posts)  [Biography] bio   Moderator
Date Reply #3 on Wed 13 Jul 2005 03:15 PM (UTC)  [ quote  ]
Message
*nod* A common global def would be "log_buf" but I think buf is too common to be used as a global def.
Zeno McDohl,
Owner of Bleached InuYasha Galaxy
http://www.biyg.org
[Go to top] top
Posted by David Haley   USA  (3,881 posts)  [Biography] bio   Moderator
Date Reply #4 on Wed 13 Jul 2005 05:05 PM (UTC)  [ quote  ]
Message
I didn't realize shadowing is an error-inducing problem (although it can make for very hard-to-track bugs...) What the compiler is supposed to do is use the local-most variable - nice compilers emit warnings, not errors, about shadowing. This might be a C++ vs C thing, though; I haven't coded in straight C for a while and have no reason to. :-)
David Haley aka Ksilyan
Head Programmer,
Legends of the Darkstone

http://david.the-haleys.org
[Go to top] top
Posted by Greven   Canada  (835 posts)  [Biography] bio
Date Reply #5 on Wed 13 Jul 2005 06:21 PM (UTC)  [ quote  ]
Message
I beleive that it is produced as an error by the pedantic flag, but I could be wrong.
Nobody ever expects the spanish inquisition!

darkwarriors.net:4848
http://darkwarriors.net
[Go to top] top
Posted by David Haley   USA  (3,881 posts)  [Biography] bio   Moderator
Date Reply #6 on Wed 13 Jul 2005 06:40 PM (UTC)  [ quote  ]
Message
Even so, when I compile I use the highest warning levels, pedantic etc., and I've never gotten that error.

I just wrote the following:
Quote:

#include <stdio.h>

int i = 3;

int main()
{
    int i = 4;

    printf("Hello there: %d\n", i);

    return 0;
}

And tested it:
dhaley@muri5 ~/tmp
$ gcc -Wall --pedantic test.c -o test

dhaley@muri5 ~/tmp
$ ./test
Hello there: 4

dhaley@muri5 ~/tmp
$
As expected, we get 4. Didn't even get a warning about a shadowing... strange. Note that it's all C, not C++, for what it's worth.
David Haley aka Ksilyan
Head Programmer,
Legends of the Darkstone

http://david.the-haleys.org
[Go to top] top
Posted by Raz   (32 posts)  [Biography] bio
Date Reply #7 on Thu 14 Jul 2005 03:20 PM (UTC)  [ quote  ]

Amended on Thu 14 Jul 2005 03:21 PM (UTC) by Raz

Message
Quote:
Even so, when I compile I use the highest warning levels, pedantic etc., and I've never gotten that error.


-Wall does not warn about shadowing. You need to turn on -Wshadow to do that.
-Raz
C++ Wiki: http://danday.homelinux.org/dan/cppwiki/index.php
[Go to top] top
Posted by David Haley   USA  (3,881 posts)  [Biography] bio   Moderator
Date Reply #8 on Thu 14 Jul 2005 04:47 PM (UTC)  [ quote  ]
Message
Even so, that is a warning, not an error, so I'm not sure where this error is coming from. Unless of course the OP really meant warning, not error.
David Haley aka Ksilyan
Head Programmer,
Legends of the Darkstone

http://david.the-haleys.org
[Go to top] top
Posted by Greven   Canada  (835 posts)  [Biography] bio
Date Reply #9 on Thu 14 Jul 2005 07:46 PM (UTC)  [ quote  ]

Amended on Thu 14 Jul 2005 07:49 PM (UTC) by Greven

Message
Could have the flag that turns warning into errors on. Can't remember what it is off the top of my head, though.

[edit]

I think it's -Werror
Nobody ever expects the spanish inquisition!

darkwarriors.net:4848
http://darkwarriors.net
[Go to top] top
Posted by Robert Powell   Australia  (349 posts)  [Biography] bio
Date Reply #10 on Fri 15 Jul 2005 12:30 AM (UTC)  [ quote  ]

Amended on Fri 15 Jul 2005 12:33 AM (UTC) by Robert Powell

Message
With -Werror it will not compile with a warning.
EldhaMUD Game Developments
The_Fury: Lead Developer, Head Coder
http://fury.eldhamud2.org
[Go to top] top
Posted by David Haley   USA  (3,881 posts)  [Biography] bio   Moderator
Date Reply #11 on Fri 15 Jul 2005 12:43 AM (UTC)  [ quote  ]
Message
Right... -Werror makes it treat warnings as errors, like Greven said. :)
David Haley aka Ksilyan
Head Programmer,
Legends of the Darkstone

http://david.the-haleys.org
[Go to top] top

The dates and times for posts above are shown in Universal Co-ordinated Time (UTC).

To show them in your local time you can join the forum, and then set the 'time correction' field in your profile to the number of hours difference between your location and UTC time.

5,231 views.

[Reply to this subject]  Reply to this subject   [New subject]  Start a new subject   [Refresh] Refresh page

Go to topic:           Search the forum

[Go to top] top

[Home]

Written by Nick Gammon - 5K

Comments to: Gammon Software support
[RH click to get RSS URL] Forum RSS feed ( http://www.gammon.com.au/rss/forum.xml )

[Best viewed with any browser - 2K]    [Internet Contents Rating Association (ICRA) - 2K]    [Web site powered by FutureQuest.Net]