Hi,

I am a beginner with programming on linux.

I need to write a program using Libpcap
I downloaded and installed the package from tcpdump.org and can see the library libpcap.a at the location /usr/lib.

I have the following sample program named as test.c:

#include <stdio.h>
#include <pcap.h>

int main(int argc, char *argv[])
{
char *dev, errbuf[PCAP_ERRBUF_SIZE];

dev = pcap_lookupdev(errbuf);
if (dev == NULL) {
fprintf(stderr, "Couldn't find default device: %s\n", errbuf);
return(1);
}
printf("Device: %s\n", dev);
return(0);
}



Following are the steps using which i compile it

gcc -c test.c
gcc test.o -lpcap
./test.o
-bash: ./test1.o: cannot execute binary file

I don't know why i am getting the above error . I changed the permission of the object file to 777, it still does not work. Any other c program runs perfectly fine.

Any help in this will be appreciated.

Regards,
Sonia

The problem is that test.o es an object file, not an ELF. So you should look for the a.out file generated after the second gcc line. If you want to name it something else you could add -o myProgram when you do your second gcc line (the linking).


Cheers!

You should also be able to do the compile and link as one step, e.g.:
which would generate an executable binary named 'test'

thanks! it worked