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.
Related
I did setup a C project with Eclipse Photon (4.8.0) for developing a program for the ESP-32. I did configure the IDE according to this official setup instructions.
Flashing the ESP-32 works fine. But as soon as I try to include header files from a sub folder, I run into troubles. I have set up a very simple project to illustrate the issue. The project consists of main.c, base/test.h and base/test.c, whereas the test.h and test.c files only contain one function with the signature void function1(void);.
When I try to call function1() in main.c, I get this error in main.c:
Undefined reference to function1()
Please compare to the attached screenshot, where everything is depicted.
How to solve this issue?
This is not a compiler, but rather a linker error.
Note, with #includeing a header file, you only make the external function known to the compiler. You also need to link to the external function during the linking stage. Make sure you include the compiled object file that contains function1 into the link.
Seems like you need to do proper linking.
If you are linking with a library, you need to specify:
The name of the library: Project\Settings\C C++ General\Paths and Symbols\Libraries
Location where the linker should search for this library:
Project\Settings\C C++ General\Paths and Symbols\Library Paths
Important: see Note.
If you are linking with object files, add those to:
Project\Settings\C C++ Build\Settings\Linker\Miscellaneous\Other objects
Note:
If your library name is, for example, libsomething.a, than you need to specify only something as the name; so omit lib prefix and .a suffix.
If your library is not prefixed with lib, then you need to add its name prefixed with :. For example, something.a should be added as :something.a.
I'm trying to use ftd2xx.lib with lcc-win32 compiler but the linker fails. I used CDM v2.12.14 but also previous FTDI driverd give the same errors. I tried to compile on Windows XP and Windows7; same results.
If I link the static library I will get these kind of errors:
File ftd2xx.lib contains unknown section .text$mn.
.text section assumed
File ftd2xx.lib contains unknown section .data$r.
.data section assumed
.data$r: undefined reference to '??_7type_info##6B#'
.text$mn: undefined reference to '__imp__SetupDiGetClassDevsA#16'
.text$mn: undefined reference to '__imp__SetupDiEnumDeviceInterfaces#20'
If I link the dynamic ftd2xx.lib (with ftd2xx.dll placed in the same dir of .exe file) I will get this:
Error e:\c\ftdi_cnt\main.c 11 undefined reference to __imp__FT_Open
(Note that main.c used for this test contains just a single FT_Open() call).
Is there anyone that was able to run ftd2xx.lib with lcc-win32 compiler or that is currently using lcc-win32 and can make a quick test? Here is the latest FTDI driver. Thank you.
Finally it works!
Here is what I did:
1) Ian suggested I should use "Utils --> Import foreign library"; as a matter of fact this is the same of running from the command line:
pedump /EXP ftd2xx.lib >ftd2xx.exp
buildlib ftd2xx.exp ftd2xxy.lib
I've already tried that using for ftd2xx.lib the dynamic .lib but without success.
2) I ran pedump again, this time using the static .lib and I got a warning message about unknown dll name, so I edited the first line of ftd2xx.exp adding that name (ftd2xx.dll).
3) I defined FTD2XX_STATIC before including ftd2xx.h
4) I linked the new library ftd2xxy.lib
Note that you can't use "Utils --> Import foreign library" because you need to modify ftd2xx.exp before re-building the library.
I hope this could be helpful for others.
I seem to be getting the rookie error where it says, undefined reference to 'check', as shown below:
This should not be a problem, as I have in fact made a check.h and included in hiker.c, as shown below:
Does anybody know the source of this problem? I have just started using MinGW(as I wanted to learn programming C on Windows).
Here is a picture of the main function. I can add the code too if necessary:
I guess that check function is implemented in a file check.c
You must link that file also, because of your check.h export the prototype to let the compiler know how the check function is structured, but the linker needs the check function code compiled and reachable.
What you need is to compile using a command like this:
gcc -Wall hiker.c check.c -o hiker.exe
Take also note that linker is giving you another error about WinMain#16
This means that you started a windows application project, I guess you must change your project to console project type.
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
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