Thread: Using Libcurl Dev C++ Undefined Reference Errors

******SAMPLE CODE FOUND ON INTERNET:********* -compiler: devc++ 5.11 libcurl version: 7.60

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>


int main()
{

curl_global_init( CURL_GLOBAL_ALL );
CURL * myHandle = curl_easy_init ( );

// Set up a couple initial paramaters that we will not need to mofiy later.
curl_easy_setopt(myHandle, CURLOPT_USERAGENT, "Mozilla/4.0");
curl_easy_setopt(myHandle, CURLOPT_AUTOREFERER, 1 );
curl_easy_setopt(myHandle, CURLOPT_FOLLOWLOCATION, 1 );
curl_easy_setopt(myHandle, CURLOPT_COOKIEFILE, "");

// Visit the login page once to obtain a PHPSESSID cookie
curl_easy_setopt(myHandle, CURLOPT_URL, "http://www.hackthissite.org/user/login/");
// Next we tell LibCurl what HTTP POST data to submit
char *data="username=your_username_here&password=your_password_here";
curl_easy_setopt(myHandle, CURLOPT_POSTFIELDS, data);
curl_easy_perform( myHandle );

curl_easy_cleanup( myHandle );


return 0;
}

**************ERRORS:*****************

C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.cpp [Error] curl/types.h: No such file or directory
compilation terminated.
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Makefile.win recipe for target 'Untitled9.o' failed


********When I delete the "#include <curl/types.h>" from the code I get the following errors:********

C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.cpp In function 'int main()':

C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.cpp [Warning] deprecated conversion from string constant to 'char*' [-Wwrite-strings]

C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x15): undefined reference to `__imp_curl_global_init'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x1e): undefined reference to `__imp_curl_easy_init'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x3e): undefined reference to `__imp_curl_easy_setopt'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x59): undefined reference to `__imp_curl_easy_setopt'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x74): undefined reference to `__imp_curl_easy_setopt'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x90): undefined reference to `__imp_curl_easy_setopt'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0xac): undefined reference to `__imp_curl_easy_setopt'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0xbc): undefined reference to `__imp_curl_easy_perform'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0xd8): undefined reference to `__imp_curl_easy_setopt'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0xff): undefined reference to `__imp_curl_easy_setopt'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x10f): undefined reference to `__imp_curl_easy_perform'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.o Untitled9.cpp.text+0x11f): undefined reference to `__imp_curl_easy_cleanup'
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\collect2.exe [Error] ld returned 1 exit status
C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Makefile.win recipe for target 'Project8.exe' failed



How do I fix these undefined reference errors? Also, what is the equivalent of types.h header file in curl 7.60? This version of curl doesn't come with that header file.

Great advice, it compiles now but it doesn't seem to do what I expected it to do? It should take the credentials I hard code in and log in to the site with them then input to the console, but it doesn't seem to do anything; it doesn't log in, I just get the blank console popping up. I did not write this code, I took it from a website, and this is obviously my first time using libcurl. What is supposed to happen?

Originally Posted by Salem

> C:\Users\b0600539\Downloads\Dev-Cpp\MinGW64\libcurl\Untitled9.cpp
Do NOT create your personal projects in the installation directories of packages you've downloaded.

One false step, and you're wondering why NONE of your programs are working all of a sudden.

> How do I fix these undefined reference errors?
You need to edit your project linker settings, say
settings -> linker -> additional libraries.

You need to set
- the name(s) of additional libraries
- the search path(s) to those additional libraries

Alright, that's fair. Let's say I have an online dashboard, where I have to select certain options to get the data I want exported to Excel. There's an option from a drop down menu I want my program to select, then I want it to enter in hardcoded dates into two fields, and select a button that will export the data corresponding to that criteria to Excel. What types of curl functions would I be looking at to get those actions done?