Just installed the new CLion IDE and wanted to try it.
Wrote a simple C program in a single source file that has 2 functions: foo() and bar(). main() calls foo and foo calls bar.
Tried to find references of both of the funcs and got nothing. Same goes for call hierarchy. I assume I forgot to configure something.
The C file compiles with gcc.
I googled the problem but found nothing helpful.
Any ideas?
Thanks
Related
I am in despair for a simple explanation to a simple problem.
I made a program in java that I need to recode in C for performance reasons. So I learned how to program in C. The problem is that C standard libraries do not contain collections (why????) such as a hashtables, treesets, etc. So I found this: https://github.com/srdja/Collections-C.
I use CLion on windows, I know well about coding but NOTHING about compiling, CMake, Linux, etc. My question is: I want to use those external source files my project, why is that so hard ? The tutorial on the link provided above tells me to use Linux command lines and stuff that I don't understand. Online I find stuff about telling me to add commands into CMakelist, none of these work for diverse reasons. I can't even copy all the .c and .h into my project because "they are not part of the project". So can anyone tell me how to make this simple code work ?
#include <stdio.h>
#include "hashtable.h"
int main() {
Hashtable *table;
hashtable_new(&table); //this is a function that creates the new hashtable in the source code of Collections-C
return 0;
}
By the way, because I think it's the same problem, how can I have subdirectories in my project so that I can put my header files away to keep the project tree tidy? I tried to add add_subdirectories($/include) to my CMakelist.txt
I am expecting people telling me that there are many similar questions already, but none of those I found is clear to me.
Thank you if you have the patience to explain this to me.
Henri
This is for C++, but it should work for your C code. In this example, it's defining where to find the OpenSSL and Google Test headers, and how to link with the Google Test library and the OpenSSL library (which is in C, as it turns out):
cmake_minimum_required(VERSION 3.5)
project(stackexample)
set(CMAKE_CXX_STANDARD 11)
find_library(GTest required)
include_directories(${GTEST_INCLUDE_DIRS} /usr/include/openssl)
set(
SOURCE_FILES
StackExample.cpp
StackExample.h
)
add_executable(stackexample ${SOURCE_FILES})
target_link_libraries(stackexample -lgtest -lssl -lcrypto pthread)
Collections-C appears to have an installer, so you would
List the path to its installed headers in the include_directories line
List its installed library in the target_link_libraries line
The solution was to build the library then do stuff with CMake. I followed this tutorial.
I've added a new function wiringPiVersion() to wiringPi, but after I build and install the shared library, when I attempt to compile a small C program around it, I get:
wpi_ver.c:(.text+0xc): undefined reference to `wiringPiVersion'
However, when I include it in an XS based Perl module, all works well. I don't know enough about C to figure out what's going wrong here, and I've been searching for the better part of two hours trying different things to no avail.
Here's my small C program to test the new function:
#include <stdio.h>
#include <wiringPi.h>
int main (){
char * ver = wiringPiVersion();
printf("wiringPi version: %s\n", ver);
return 0;
}
Compilation that throws the error:
gcc -o ver wpi_ver.c -lwiringPi
The addition to wiringPi's header file:
extern char * wiringPiVersion(void);
The wiringPi's .c file addition:
#define WPI_VERSION "2.36"
char * wiringPiVersion(void){
return WPI_VERSION;
}
In my Perl module's XS file, I have:
char *
wiringPiVersion()
...and my Perl module's Makefile.PL
LIBS => ['-lwiringPi'],
...and after re-installing the Perl module, I can access the function without any issues in a test script.
I'm hoping this is something simple I'm overlooking which someone may be able to point out. My question is, how do I rectify this?
So it turned out that there were two .so files generated when I rebuilt wiringPi... one in the wiringPi's build directory way under my home directory, and the other in /usr/local/lib.
After a tip in comments, I added the library path explicitly:
gcc -o ver wpi_ver.c -L/usr/local/lib -lwiringPi
...and it all fell together and works as expected:
$ ./ver
wiringPi version: 2.36
Note: I have sent Gordon the patch in hopes it gets included in the next wiringPi cut.
Update: I received an email back from Gordon and he stated that currently, only the gpio application has the ability to report the version, so he advised that he's going to add something similar to my patch in a future release.
Although already solved, I added this answer to show what gave me the hint.
Error message "undefined reference" points to a linker error (cf. answer on SO), so its about checking if the correct library is drawn.
I am trying to port a program that uses GCD (Grand Central Dispatch) from OSX to Ubuntu 11.10. I installed libdispatch but I keep getting the following error:
undefined reference to dispatch_main()
The strange thing is that dispatch_main() is declared in a header file that I include and I call other functions declared in that header file and the compiler recognizes them. It is only dispatch_main() that it cannot see and if I call dispatch_main(2) it says that there are too many arguments, so I know the compiler can see the header.
I tried separating the compile and link steps (clang -c...) since that worked for an undefined reference error before, but it doesn't seem to do anything here...
Anybody have any suggestions? I'm pretty stumped on this one...
It sounds like you are missing the library from your link line. When you compile your program into an executable, add the library to the command. I am guessing it should look something like this:
clang x.c y.c z.c -ldispatch
i was trying to make a dll in C, so i found this:
http://forum.codecall.net/topic/47543-how-to-create-and-use-dll-in-c/#gsc.tab=0
i followed the last post, but i always end up having this error whenever i use the function "sum" in a client file:
[Error] C:\Users\Siegfred\Desktop\dll testing\test.c:7: undefined reference to `imp_sum'
NOTES: A. im using MinGW 5 in an IDE named C-free. B. after i compile the header and the c file for the dll, the IDE/compiler looks for an .exe which is not generated.
how do i fix this? thank you.
I'm writing some code that uses a C library provided by MATLAB (to extract data from *.mat files). In my IDE (Code::Blocks), I've included the folder containing the necessary "mat.h", which is on a network drive. My code recognises types defined in mat.h when I do this, but whenever I call functions from the file I get an "undefined reference" error. This is the same case for the example code MathWorks provides. What sort of problem usually causes this?
#include "mat.h"
int main (void) {
MATFile *pmat; // Compiles only when compiler is told to search in mat.h directory
pmat = matOpen("example_filename", "r"); // Never compiles
return 0;
}
Thanks!
Cameron
"undefined reference" is normally a linker error. It's not a problem of a header file. You need to tell the linker to link MATLAB's library (or a dedicated object) to your program.
No idea how this is done in Code::Blocks though. In the Code:Blocks documentation it is described here.
Have you checked the contents of mat.h? Does it declare matOpen()? Also, does the error occur when compiling or linking? If it's during the link phase, you probably need to reference the library that contains the implementation of matOpen() (a .lib in Windows, or .a in Unix). The .h file only declares the function.