Linking “C” Programs with the Chilkat C/C++ Libs

The Chilkat C/C++ libs are (internally) written in C++.  Therefore, when linking a “C” program with the Chilkat libs, the C++ runtime libs must be included.  This is true regardless of the operating system, whether it be Windows, MAC OS X, IOS, Linux, etc.    Different build environments will have different ways of accomplishing the task.  For example, with XCode (on Mac OS X), simply adding an empty source file having a filename with the extension “.cpp” is all that is needed.  This blog post will show how to link a “C” program on Linux with the Chilkat C/C++ static library.  The solution is to use “g++” for the link phase instead of “gcc”.  The telltale indicator that the C++ runtime libs are missing is when you see errors involving “__cxxabiv1”, such as the following:

undefined reference to `vtable for __cxxabiv1::__class_type_info'

Here is a simple C program with a simple shell script to build it correctly.

buildTest.sh (This is for 64-bit Linux. Notice that g++ is used for linking, not gcc.)

#!/bin/bash -ev

gcc -m64 -Werror -c -fmessage-length=0 -fno-stack-protector -fPIC -o"cTest.o" "cTest.c"

g++ -g0 -m64 -L"/home/chilkat/workspace/chilkat/lib64_static" ./cTest.o -o"cTest"  
    -lchilkat-9.3.0 -lpthread -lresolv

cTest.c

#include <stdio.h>
#include "../chilkat/include/C_CkFtp2.h"

void testFtp2Create(void)
    {
    HCkFtp2 ftp;
    BOOL success;

    ftp = CkFtp2_Create();

    //  Any string unlocks the component for the 1st 30-days.
    success = CkFtp2_UnlockComponent(ftp,"Anything for 30-day trial");
    if (success != TRUE) {
        printf("%s\n",CkFtp2_lastErrorText(ftp));
    }

    CkFtp2_Dispose(ftp);
    }


int main(int argc, char *argv[])
{
	testFtp2Create();
	printf("Hello World!\n");
	return 0;
}