No there is no difference between the way unix and linux resolve symbols...the thing you are seeing is the default compilation mode in hpux is c89 while in linux it is c99 which is far more stricter than c89. In fact you will get the same error if you switch the default compilation mode in hpux to c99 by adding the following switch to your command line...
Code:
cc -AC99 <blah blah blah>
Quote:
Originally Posted by snowline84
I came across a difference between Unix and Linux, when it comes to resolving the symbols from the libs.
consider the following code segments...
Code:
$ cat call1.c
#include <stdio.h>
int a1;
extern int a3;
void prnt_a3()
{
printf("\n%d\n",a3);
}
$ cat test.c
#include <stdio.h>
extern int a1;
int main()
{
int a2=20;
printf("\n%d\n",a1);
return 0;
}
Highlights are...
* a1 is defined in call1 and is being referenced in test.c and is being used also
* a3 is referenced to in test.c and is not defined anywhere. It is being used but in a dead function prnt_a3
prnt_a3 is not a dead function...it is very much live and it is supposed to print an unallocated and undefined variable a3 which is an error...there is no difference in its treatment when it comes to unix or linux...
Quote:
Originally Posted by snowline84
I am running it as
Code:
cc -g -c test.c call1.c
ar q lib.a call1.o
cc -g -o test test.o lib.a
The executable gets build in HP Unix bit in Linux, it fails saying
Code:
call1.c:6: undefined reference to `a3'
collect2: ld returned 1 exit status
Even thogh hpux generates an a.out file yet that file isnt executable...did you even try to run the a.out file produced from the compilation...on my hpux box it says it cannot execute which is true as the compilation wasnt complete and so a load module wasnt generated. Linux is somewhat smarter and gives a linker error and stops there.
Quote:
Originally Posted by snowline84
I don't know the concept/rationale behind the same.
HPUx just refers to the data definitions and it doesn't bother about the functions unless there is atleast 1 function being used from that routine (in which case, HP also gives error) ???
If anyone can suggest some reading material for the same, it'll also be great.
Thanks...
Isnt function and routine the same thing so state your problem clearly...
This may/may not be a long answer to a short question.
I am learning the C programming language at home.I have seen some good books on the UNIX programming enviroment.However, there were a few books that hinted towards the Linux programming enviroment.Is there any difference between the two as... (1 Reply)
Ok, I'm confused.
Can someone answer these (stupid) questions please for me?
1. What is the difference between unix and linux?
2. Is FreeBSD a unix distribution?
3. If not, then what is Unix? I actually gone to Unix.com because I thought this is it's official website where I could download... (1 Reply)
OK, I've used various versions of UNIX(Solaris, HPUX, etc..) over the years. Now the organization I work for is leaning towards more Linux based systems(Redhat, Suse, etc..)
I do see differences in in comands and how to accomplish basic adminstration, but nothing mind blowing.
So, what is it... (5 Replies)
:confused: Hi All
Can anyone help me in finding the answer of the question mentioned below.
What is the difference between Unix & linux ?
Thanks in Advance to all
CSaha (1 Reply)
Sir ,
Can any body explain the difference between linux , Unix and AIx on command Reference all the command on AIx and unix is same or not
please reply (2 Replies)
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10-17-2012
