Hi I want to build an application for windows in C, I program in linux and compile the code with gcc and mingw-w64.
I tried a simple program with output and input it works fine on windows.
But, I want to use sockets to connect to a server.
So I searched in google and found this tutorial http://beej.us/guide/bgnet/output/html/multipage/intro.html#audience
It says that in windows we need to include winsock and run some command
So I did:
#include <winsock.h>
int main(void)
{
WSADATA wsaData;
printf("Hello! This is a test prgoram.\n");
if (WSAStartup(MAKEWORD(1,1), &wsaData) != 0) {
fprintf(stderr, "WSAStartup failed.\n");
}
}
But when I try to compile it I get:
undefined reference to `__imp_WSAStartup'
collect2: error: ld returned 1 exit status
In command line all that I run was:
x86_64-w64-mingw32-gcc try.c -o a.exe
So what I should do?
If I compile in linux I don't need the winsock library?
How to fix this?
thanks
If you look at the WSAStartup Manual and scroll a bit down, you will find what library it is defined in: Ws2_32.lib
This is an "import library", a stub you need to link against for a windows program to use the respective DLLs. MinGW includes all standard windows platform import libraries. So you just need to link it, using -lws2_32.
Related
I'm new in winAPI and I was learning how code programs with some special functions and such, so I downloaded the Windows's SDK.
Problem is, GCC decided to put the blind glasses and say:
Documents_path.c:6:25: fatal error: KnownFolders.h: No such file or directory
#include<KnownFolders.h>
^
compilation terminated.
I said "OK, next one then" and there's another header with the same problem:
thread.c:3:30: fatal error: processthreadsapi.h: No such file or directory
#include<processthreadsapi.h>
^
compilation terminated.
I checked if these headers are even in my PC and here they are setting with windows.h, which it was working when I tried basic functions with it.
I searched an answer for this problem but didn't find any, either it was a external\binary libraries problem, is it local or not or a macro fix (which it didn't work).
How can I fix the problem?
EDIT:
I'm using VS Code
EDIT2:
This is the code of "Documents_path.c" example:
#include<stdio.h>
#include<stdlib.h>
#include<Windows.h>
#include<ShlObj.h>
#include<initguid.h>
#include<KnownFolders.h>
#pragma comment(lib, "user32.lib")
int main(){
int a;
PWSTR path = NULL;
HRESULT hr = SHGetKnownFolderPath(&FOLDERID_Documents, 0, NULL, &path);
if(SUCCEEDED(hr)){
printf("path for Documents is: %ls", path);
}
scanf("%d",&a);
CoTaskMemFree(path);
return 0;
}
And I'm reading the basics of winAPI from this website:
https://zetcode.com/gui/winapi/
as for structure of project folder:
C:\Users\ %USER%\Documents\C\dawd
MSVC uses Windows SDK while GCC does not.
On Windows GCC uses MinGW or MinGW-w64 as standard library, which is an open source implementation of Windows API.
So GCC+MinGW will use its own headers and will not look for any Windows SDK. So GCC+MinGW on Windows works without having any Microsoft developer tools installed at all.
MinGW-w64 - which is more recent than MinGW and which supports both Windows 32-bit and 64-bit - exists in a standalone package that can be downloaded from https://winlibs.com/. But you can still use it from an IDE like VSCode or Code::Blocks.
MinGW-w64 has the files like knownfolders.h and processthreadsapi.h which you had issues with.
But be aware that #pragma comment(lib, "user32.lib") is MSVC-specific and will not work in other compilers like GCC. Instead you must use linker flag -luser32. Because you call CoTaskMemFree() you will also need to add -lole32.
I tried your code on my system and it compiles and links fine with:
gcc -c -o Documents_path.o Documents_path.c
gcc -o Documents_path.exe Documents_path.o -luser32 -lole32
I'm new to using wolfSSL. I am trying to compile a set of codes using gcc.
gcc -o main main.c -lwolfssl
I encounter an error of main.c:(.text+0x47b): undefined reference to 'wolfSSL_get_peer_certificate'
collect2: error: ld returned 1 exit status upon entering the statement.
A snippet of the code shows the error location:
fprintf(stderr, "ERROR: failed to connect to wolfSSL\n");
return -1;
}
ret = certverify(CERT_FILE,verifyCert);
WOLFSSL_X509* webCert = wolfSSL_get_peer_certificate(ssl);
I have tried modifying the WOLFSSL_X509* webCert = wolfSSL_get_peer_certificate(ssl); command but it seems to be correct.
I am not too sure why this error is occuring. Can someone please help me with this?
I am using Kali Linux 2019.4 to compile this set of codes.
#wolfSSL_new,
It sounds like the application is failing to link the library so while the right headers are in place to locate the function definitions the final step to link the function is what is failing. Where is libwolfssl.so or libwolfssl.a located on your system? Is it in /usr/local/lib/libwolfssl.so or /usr/local/lib/libwolfssl.a?
(.a is a static library, .so is a shared object library it can be either or)
Once you located where it is try this build command instead (For the sake of an example I am going to assume it is in /usr/local/lib):
gcc main.c -o main -I/usr/local/include -L/usr/local/lib -lwolfssl
Let me know if that resolves the linker error you are seeing.
[UPDATE]
This was resolved by adding the configure setting --enable-opensslextra
[END UPDATE]
Regards,
K
I am new to Tcl scripting and would like to use C to embed Tcl codes.
This is the code that I have copied from a website to test the Tcl-C working.
test.c
#include <stdio.h>
#include <tcl.h>
void main ()
{
Tcl_Interp *myinterp;
char *action = "set a [expr 5 * 8]; puts $a";
int status;
printf ("Your Program will run ... \n");
myinterp = Tcl_CreateInterp();
status = Tcl_Eval(myinterp,action);
printf ("Your Program has completed\n");
getch();
}
I am using MinGW to compile this file.
I have copied the contents of the C:\Tcl\include folder into the C:\MinGW\include folder as well.
My gcc command for compiling :
gcc -o test.exe test.c
The error message shown :
C:\Users\user\AppData\Local\Temp\ccEHJKCb.o:tcl_connection_test.c:(.text+0x23): undefined reference to `_imp__Tcl_CreateInterp'
C:\Users\user\AppData\Local\Temp\ccEHJKCb.o:tcl_connection_test.c:(.text+0x3d): undefined reference to `_imp__Tcl_Eval'
c:/mingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\Users\user\AppData\Local\Temp\ccEHJKCb.o: bad reloc address 0x20 in section `.eh_frame'
c:/mingw/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: final link failed: Invalid operation
collect2.exe: error: ld returned 1 exit status
I don't seem to have any libtcl file in the Tcl folder.
The Tcl version is ActiveTcl 8.5.15.0.297577.
Any help would be really appreciated.
Your example how to embed Tcl is outdated, and you are missing certain things in your link line (-ltcl85 for example). If you simply add -ltcl85 to your link line it should start to work.
It does not work in your case, because you installed the x64 (64-Bit version) of ActiveTcl, which provides x64 dlls, not 32-Bit ones. But the standard mingw gcc only works with 32-Bit libraries.
So to get this to work:
Download the 32-Bit ActiveTcl distribution
Compile your code with gcc -o test.exe test.c -Lc:/tcl/lib -Ic:/tcl/include -ltcl86
Adjust your path so the c:\tcl\bin\tcl86.dll is found in PATH, make also sure Tcl finds its libdir (set TCL_LIBRARY=c:\tcl\lib\tcl8.6)
run your program
But for more complex examples, you still need to initialise the library and a do some boilerplate code, so please call Tcl_FindExecutable(argv[0]); before the call to Tcl_CreateInterp() otherwise a few commands (e.g. clock might just not work as expected).
Have a look at http://www.tcl.tk/cgi-bin/tct/tip/66.html for some more details. Also have a look at the Tcl source distribution and the source for the tclsh shell.
You're very close to getting it right.
The Tcler's Wiki has a few examples, some of which are very confusing to be frank, but this one from this page is the best I've spotted recently. (The comments are mine.)
#include <stdlib.h>
#include <tcl.h>
int main (int argc, char *argv[]) {
Tcl_Interp *interp;
const char *script = "proc p1 a { puts $a }";
// Initialize the Tcl library; ***STRONGLY RECOMMENDED***
Tcl_FindExecutable(argv[0]);
// Create the interpreter, the execution context
interp = Tcl_CreateInterp();
// Initialise the interpreter
if (TCL_OK != Tcl_Init(interp)) {
fprintf(stderr, "Tcl_Init error: %s\n", Tcl_GetStringResult(interp));
exit(EXIT_FAILURE);
}
// Define a procedure
Tcl_Eval(interp, script);
fprintf(stderr, "res 1: %s\n", Tcl_GetStringResult(interp));
// Check if the procedure exists
Tcl_Eval(interp, "puts [info commands p*]");
fprintf(stderr, "res 2: %s\n", Tcl_GetStringResult(interp));
// Call the procedure
Tcl_Eval(interp, "p1 abc");
fprintf(stderr, "res 3: %s\n", Tcl_GetStringResult(interp));
// We could use Tcl_DeleteInterpreter to clean up here, but why bother?
return EXIT_SUCCESS;
}
What else were you missing? Simple. You forgot to tell the C compiler to use the Tcl library when building the executable; the compiler (or, more strictly, the linker) is in places a stupid piece of code. The exact option to use to get the linker to add the library in will depend on your system configuration, but is probably going to be -ltcl, -ltcl8.5 or -ltcl8.6; which it is depends on the filename and all sorts of things that we can't check exactly without being on your system. The names do fit a simple pattern though.
It's also possible that you might need to pass the -L option in to tell the linker about additional library locations. (There's an equivalent -I for telling the compiler where to find include files, so you don't have to copy everything into one gigantic unmanageable directory.)
The order of arguments can matter. Libraries should be listed after the source file:
gcc -o test.exe test.c -L/mingw/path/to/library/directory -ltcl86
(If you're using old, unsupported versions of Tcl — why would you do that?! — then the code above won't work because Tcl_Eval then took a writable string. But that was fixed many years ago and upgrading to a current version is the fix.)
I recently started SDL2.0 programming.
I did a lot of researches and i tried all but i still get those "undefined reference" errors for all the SDL functions:
undefined reference to `SDL_Init'|
undefined reference to `SDL_GetError'|
undefined reference to `SDL_Quit'|
||=== Build finished: 3 errors, 0 warnings ===|
on that simple test program:
#include <stdlib.h>
#include <stdio.h>
#include "SDL.h"
int main(int argc, char* argv[])
{
if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0) {
fprintf(stderr, "\nUnable to initialize SDL: %s\n", SDL_GetError());
return 1;
}
atexit(SDL_Quit);
return 0;
}
If i have to guess the problem occurs due to the wrong command line syntax.
In this case what should be the correct one?
You aren't linking to the SDL libraries correctly.
Add the following lines int Other Linker Option
-lSDL -lSDLmain
mingw32
SDLmain
SDL
Also You need to check setup for how to compile SDL in codeblock
http://wiki.codeblocks.org/index.php?title=Using_SDL_with_Code::Blocks
http://lazyfoo.net/SDL_tutorials/lesson01/windows/codeblocks/
If it's not too late then try from the beginging to how to set up SDL in codeblock and successfully run it? Below link provide you exact steps for it.
http://www.dreamincode.net/forums/topic/57275-setting-up-codeblocks-to-work-with-sdl/
You might have not linked SDL2 correctly to your CodeBlocks project and not referred to SDL2 correctly in your code.
1:
Go to "Linker options" in "Build Options" menu and make sure you have added these library's to your project like this:
Library's to include in linker options
Importent!: save project before running it after adding/changeing library's.
2:
Change:
#include "SDL.h"
to this:
#include <SDL2/SDL.h>
if you still encounter problems compiling and running it, it's most likely either, your SDL2 files not placed correctly in the compiler's folders, or your using an version of gcc with some missing tools.
These Youtube video's explain everything in great detail:
1: https://www.youtube.com/watch?v=x0LUf7Ibpi0
2: https://www.youtube.com/watch?v=EtUw_7CvRRo
I'm trying to create a client for a web service in C. I was generated C files with the wsdl2h and soapcpp2. In netbeans I'm added the generated files and the gSOAP include dir to the project's include directories.
my main file looks like this:
#include <stdio.h>
#include <stdlib.h>
#include <soapH.h>
#include <webserviceSoap12.nsmap>
int main(int argc, char** argv) {
struct soap *soap1 = soap_new();
struct _ns1__getAllCustomer *quote;
struct _ns1__getAllCustomerResponse *quote2;
if (soap_call___ns2__getAllCustomer(soap1, NULL, NULL, quote, quote2) == SOAP_OK)
printf("asd\n");
else // an error occurred
soap_print_fault(soap1, stderr); // display the SOAP fault on the stderr stream
return (EXIT_SUCCESS);
}
I copied the most of this from the gSOAP website's getting started section.
When I try to compile i get the following error:
build/Debug/MinGW-Windows/main.o: In function `main':
\NetBeansProjects\WebServiceClient/main.c:19: undefined reference to `soap_new_LIBRARY_VERSION_REQUIRED_20808'
\NetBeansProjects\WebServiceClient/main.c:22: undefined reference to `soap_call___ns2__getAllCustomer'
\NetBeansProjects\WebServiceClient/main.c:25: undefined reference to `soap_print_fault'
If I add the "soapC.c" "soapClient.c" "soapClientLib.c" files to the project I get a bunch of more undefinied reference.
What am I doing wrong? I'm using Netbeans ide with MinGW compiler on Win7. What other libraries I need or what other files should I include?
I managed to solve the problem by adding the files "soapC.c" "soapClient.c" "stdsoap.c" to the project files and in the Project propertie - Include Directories adding the files generated by soapcpp2 and the gSOAP toolkit's gsoap directory
You will need to link in the proper libraries. You will need to add the appropriate libraries using the -l switch and you will optionally need to pass the path to where these libraries reside via -L. Also, note that the libraries ending with a ++ are typically the ones you should use if you're using C++. So, your command line shoulde include at least:
For C:
gcc ... -lgsoap -L/path/to/gsoap/binaries
For C++:
g++ ... -lgsoap++ -L/path/to/gsoap/binaries
Also, depending on whether you're using additional features such as SSL, cookies etc. you will need to link these libraries in too:
g++ ... -lgsoap++ -lgsoapssl++ -L/path/...
If you're using a different toolchain, lookup the documentation for the exact switches.
I had this problem in Debian BullsEye (11), -lgsoap++ is necessary and it was solved when I added /gsoap_library_path/libgsoap++.a to g++ compiler command line.