# Error -128 calling k(0, ...) from same process **URL:** \ **Category:** Community Support\ **Tags:** kdb-and-q\ **Created:** [September 5, 2014, 5:45pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045 "2014-09-05T17:45:00Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![samsogade](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@samsogade](https://forum.kx.com/u/samsogade)\ **Post date:** [September 5, 2014, 5:45pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/1 "2014-09-05T17:45:00Z")
In my shared object I have K ret = k(0, (S)“0N!`hello”, (K)0); If I call the above code from the current process I receive ret == -128 and ret-\>s will return (null). However, if I open two processes, one listening on port 5010 and another process with the code K handle = kph((S)“localhost”, 5010); K ret = k(0, (S)“0N!`hello”, (K)0); There are no problems, and the process running on port 5010 will as expected print  `hello `hello Any ideas why I can run the code in the same process? ---
**Author:** ![charlie1](https://avatars.discourse-cdn.com/v4/letter/c/ec9cab/32.png) [@charlie1](https://forum.kx.com/u/charlie1)\ **Post date:** [September 5, 2014, 5:50pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/2 "2014-09-05T17:50:00Z")
for a shared object, do not link with c.o as those functions etc already exist within the kdb+ process. ---
**Author:** ![samsogade](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@samsogade](https://forum.kx.com/u/samsogade)\ **Post date:** [September 5, 2014, 6:08pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/3 "2014-09-05T18:08:00Z")
Thanks Charles. How can I compile anything without linking to c.o? I can send the data from one q process to another, but not to itself where the shared object is loaded, i.e. k(0,…)? ---
**Author:** ![samsogade](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@samsogade](https://forum.kx.com/u/samsogade)\ **Post date:** [September 5, 2014, 6:09pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/4 "2014-09-05T18:09:00Z")
Apologies, the code above should read K handle = kph((S)“localhost”, 5010); K ret = k(handle, (S)“0N!`hello”, (K)0); ---
**Author:** ![charlie1](https://avatars.discourse-cdn.com/v4/letter/c/ec9cab/32.png) [@charlie1](https://forum.kx.com/u/charlie1)\ **Post date:** [September 5, 2014, 6:13pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/5 "2014-09-05T18:13:00Z")
to create a shared lib on linux using gcc, the cmd line for compiling would be gcc -DKXVER=3 a.c -o a.so -fPIC -shared the functions such as ktn etc are resolved when loading into kdb+. ---
**Author:** ![charlie1](https://avatars.discourse-cdn.com/v4/letter/c/ec9cab/32.png) [@charlie1](https://forum.kx.com/u/charlie1)\ **Post date:** [September 5, 2014, 7:13pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/6 "2014-09-05T19:13:00Z")
btw, for developing shared libs, refer to http://code.kx.com/wiki/Cookbook/ExtendingWithC noting that if you are developing a lib to load into kdb+2.x define KXVER=2 and for v3.x define KXVER=3 ---
**Author:** ![samsogade](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@samsogade](https://forum.kx.com/u/samsogade)\ **Post date:** [September 11, 2014, 3:38pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/7 "2014-09-11T15:38:00Z")
Thanks a lot! One more issue: My dynamic shared object does not contain any exported symbols. My C++ code contains some functions that are defined like extern “C” myfunc(). From the terminal I can see that myfunc() is not being exported: nm -f feed\_handler.so U dyld\_stub\_binder file feed\_handler.so          feed\_handler.so: Mach-O dynamically linked shared library i386 Is my compilation messed up? ---
**Author:** ![charlie1](https://avatars.discourse-cdn.com/v4/letter/c/ec9cab/32.png) [@charlie1](https://forum.kx.com/u/charlie1)\ **Post date:** [September 11, 2014, 4:59pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/8 "2014-09-11T16:59:00Z")
can you provide a very simple test cpp file, .e.g #include"k.h" extern “C” K f(K x){R (K)0;} and your compile cmd line? and compiler version ---
**Author:** ![samsogade](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@samsogade](https://forum.kx.com/u/samsogade)\ **Post date:** [September 12, 2014, 6:24pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/9 "2014-09-12T18:24:00Z")
Ok, so I can compile your example. However, if I use other functions such as k(), ki(), khp(), etc. I’m getting ‘Undefined symbols’: #include “k.h” extern “C” K f(K x){R (K)0;} extern “C” K add(K x,K y) { R ki(x-\>i+y-\>i); } compiling: clang++ -DKXVER=3 -m32 -fPIC -shared -stdlib=libc++ -std=c++11 test.cpp -o test.so Undefined symbols for architecture i386: “\_ki”, referenced from: \_add in test-d49315.o ld: symbol(s) not found for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation) ---
**Author:** ![charlie1](https://avatars.discourse-cdn.com/v4/letter/c/ec9cab/32.png) [@charlie1](https://forum.kx.com/u/charlie1)\ **Post date:** [September 12, 2014, 6:59pm UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/10 "2014-09-12T18:59:00Z")
i think you need -undefined dynamic\_lookup  ---
**Author:** ![samsogade](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@samsogade](https://forum.kx.com/u/samsogade)\ **Post date:** [September 14, 2014, 11:53am UTC](https://forum.kx.com/t/error-128-calling-k-0-from-same-process/9045/11 "2014-09-14T11:53:00Z")
Thanks a lot Charles