Solved

GCC/Sockets/link

Posted on 1997-10-14
10
1,229 Views
Last Modified: 2013-12-26
I wrote small CGI (C language), and it using sockets. Source code compiles without any problem, but during linking I've got messages

Undefined                       first referenced
 symbol                             in file
socket                              /var/tmp/cca000Ms1.o
inet_addr                           /var/tmp/cca000Ms1.o
sendto                              /var/tmp/cca000Ms1.o
shutdown                            /var/tmp/cca000Ms1.o  

So, I guess, GCC does not see some libraries
Does enybody know, which flags should I use, to include this library into linking process ?
Thanks in advance
Alexey Trofimov
0
Comment
Question by:trof
10 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 1295284
try
cc -lsocket
0
 
LVL 51

Expert Comment

by:ahoffmann
ID: 1295285
Which OS do you have?
For most UNIXs they should be in  libc.a and/or libc.so.
0
 
LVL 1

Author Comment

by:trof
ID: 1295286
SunOS 5.5.1
GCC 2.7.2.1
Actually, GCC -lsocket works for all entries, except "inet_addr"...

0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 1

Author Comment

by:trof
ID: 1295287
oooppss, sorry, maybe, it's another error...

Undefined                       first referenced
 symbol                             in file
inet_addr                           /var/tmp/cca0006H1.o  (symbol belongs to imp
licit dependency /usr/lib/libnsl.so.1)
   
So, what I suppose to do now ?
0
 
LVL 51

Expert Comment

by:ahoffmann
ID: 1295288
try to find the library which contains the requested symbol, add this library to your link command.

#! /bin/csh -f -b
foreach l (/usr/lib/lib*.so.*)
echo ------------- $l
nm -gop $l | grep inet_addr
end
0
 
LVL 1

Author Comment

by:trof
ID: 1295289
Thanks, I guess, how it suppose to work, but

------------- /usr/lib/libC.so.3
nm: Command not found

Ok, let's say, I found 5-10 files, include "inet_addr". Some of them just call this function, right ? How I know witch one does contain real code of this function(not just call of it ) ? And if I know exactly name of proper file, what should I type in command line of GCC ?
0
 
LVL 51

Expert Comment

by:ahoffmann
ID: 1295290
no nm? Sounds strange. Do you need a path to it?

Anyway, nm reports the referenced and defined symbols in a library. Defined (text) symbols are marked  T  or  t, undefined (referenced) symbols are marked  U. This is how you can find the right library.

Of cause my shell example could be more sophisticated to get only the desired names, but this also should report what you need.

If you have no  nm,  strings  (without options) could be used, but it does not give you a hint if its defined or referenced.

Should I've marked it as answer ;-)

0
 
LVL 4

Expert Comment

by:jos010697
ID: 1295291
I'm astonished ... the entire socket stuff is supposed to
be part of libc.a. Are you sure you're linking in the
correct libc.a, i.e. /usr/lib/libc.a (or equivalent).

Could you show the actual command line you're using for
the linkage of this all?

kind regards,

Jos aka jos@and.nl
0
 
LVL 4

Accepted Solution

by:
rembo earned 260 total points
ID: 1295292


Actually, you need

-lsocket -lnsl

on your link line.  That's the SVR4 approach :)

-Tony


0
 
LVL 51

Expert Comment

by:ahoffmann
ID: 1295293
Unfortunately I'm off from Solaris (SunOS 5.x), that's why I suggested to search for the symbols in the existing libs.

As far as I could remember  -lnsl  is the the approach, thanks rembo. As closer as one get to SVR4  -lsocket  is it too :)
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Get filename and folder into excel 7 84
ODBC Connection Logging, ADO.NET 6 71
VBA "SendKeys" Syntax for Multiple Keystrokes 7 125
lucky13 challenge 11 158
Here is how to use MFC's automatic Radio Button handling in your dialog boxes and forms.  Beginner programmers usually start with a OnClick handler for each radio button and that's just not the right way to go.  MFC has a very cool system for handli…
Introduction: The undo support, implementing a stack. Continuing from the eigth article about sudoku.   We need a mechanism to keep track of the digits entered so as to implement an undo mechanism.  This should be a ‘Last In First Out’ collec…
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
Nobody understands Phishing better than an anti-spam company. That’s why we are providing Phishing Awareness Training to our customers. According to a report by Verizon, only 3% of targeted users report malicious emails to management. With compan…

740 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question