By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
440,740 Members | 844 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 440,740 IT Pros & Developers. It's quick & easy.

Calling a C library function from within C++

P: n/a
I'm having a problem calling a C function from a publicly available
library file. To get the code to compile, I had to declare the
function as an external C function as follows.

extern "C" lib_function(....);

But when I run my C++ program, I get a segmentation fault in one
of the library functions (not the function I directly called but
one a few levels down in the calling hierarchy). According to
the user manual provided with the library, I'm passing in the
arguments correctly and I've allocated space for the arrays being
passed (each argument is either an integer or an array of integers),
hence I suspect the problem has something to do with the fact that
I'm calling a C function from within C++. (the authors claim that
the C code has no known bugs).

Any ideas on what the problem could be?

Note that I am using the gcc/g++ compiler on UNIX. In case you're
interested, the library package I'm using is called HMETIS and is
available at http://www-users.cs.umn.edu/~karypis/metis/

Also if you want to respond via email, then send your message to
rhoads <at> paul <dot> rutgers <dot> edu (the yahoo.com address
is bogus).

[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]
Jul 22 '05 #1
Share this Question
Share on Google+
3 Replies


P: n/a
Glenn C. Rhoads wrote:
I'm having a problem calling a C function from a publicly available
library file. To get the code to compile, I had to declare the
function as an external C function as follows.

extern "C" lib_function(....);
I trust you don't have the dots in the actual code.
But when I run my C++ program, I get a segmentation fault in one
of the library functions (not the function I directly called but
one a few levels down in the calling hierarchy).
Not an unusual thing at all.
According to
the user manual provided with the library, I'm passing in the
arguments correctly
You ought to say "according to my reading of the manual".
and I've allocated space for the arrays being
passed (each argument is either an integer or an array of integers),
hence I suspect the problem has something to do with the fact that
I'm calling a C function from within C++. (the authors claim that
the C code has no known bugs).

Any ideas on what the problem could be?
Nope. Run it under a debugger. Let it crash and analyse the contents
of the variables. If you can find the source code for the library,
build it again with debugging information, and debug it.
Note that I am using the gcc/g++ compiler on UNIX. In case you're
interested, the library package I'm using is called HMETIS and is
available at http://www-users.cs.umn.edu/~karypis/metis/


Post the short version of how you use it (unless you manage to find
the error before that).

Victor
Jul 22 '05 #2

P: n/a
Glenn C. Rhoads wrote:
I'm having a problem calling a C function from a publicly available
library file. To get the code to compile, I had to declare the
function as an external C function as follows.

extern "C" lib_function(....);

What is the declaration of the fuction in C?

[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]
Jul 22 '05 #3

P: n/a
GTO
I assume that you know this

http://www.parashift.com/c++-faq-lit...c-and-cpp.html

Gregor
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]
Jul 22 '05 #4

This discussion thread is closed

Replies have been disabled for this discussion.