clangd language server gives weird errors. code compiles - c++

I've got platformio project that compiles and works.
Using emacs + lsp-mode + clang.
One of the weird errors I get is for structures like this:
#include <queue>
#include <vector>
struct test_v{
std::vector<int> buff;
};
on the line #include <queue>
in included file: no type named 'pointer' in 'std::allocator_traits<std::allocator<int>>'
on the line of buff definition
In template: no member named 'value' in 'std::is_void<int>'
file is .hpp in case this matters


the config was incomplete and missing headers that define the needed std:: parts

Related

Policy data structure on my compiler is not working

I want to use a policy based data structure but my compiler keeps on giving me errors.
Here is what im using in my code:
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <typename T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
Here are the error messages I recieve:
fatal error:
'ext/typelist.h' file not found
#include <ext/typelist.h>
and
error: function-like macro
'__GLIBC_PREREQ' is not defined
#if __GLIBC_PREREQ(2,15) && defined(_GNU_SOURCE)
I've tried replacing the files over and over again but it keeps on telling me to continuously add new files that my computer does not have. I am using VS Code on a mac. Thank you.

The macro __GLIBC_PREREQ is defined in <cstdlib> , it is not to be guaranteed to be included by default. It looks like you had omitted some vital header or the implementations of those headers don't include <cstdlib>
PBDS requirec gcc, saying that you use VSCode IDE doesn't tell what compiler you're using.

After defining a function in another file, visual studio does not recognize the function

I'm creating windows console app that has many pages (split in files). I'm facing a problem when executing the program and Visual Studio throws 'startpage' identifier not found error (startpage is the function and the file name is startpage.h)
I've tried using:
external int startpage(); and
int startpage();.
I've tried changing only the function name too (so the file and function don't use the same name).
I have no idea why this is happening. Other files with different functions are working. The file "startpage.h" uses two functions defined in other files, and those are not throwing any errors.
#include "include/startpage.h"
#include <iostream>
#include <conio.h>
#include "include/concol.h"
#include "pch.h"
#include <iostream>
using namespace std;
int main()
{
startpage();
}
```
Here is the error:
Error code: C3861: 'startpage' identifier not found

Move #include "pch.h" to the top. The compiler ignores everything above the inclusion of precompiled header. – Igor Tandetnik
This worked!
Thank you so much guys!

Emscripten: algorithm.h file not found

I am trying to compile the following code:
#include<stdio.h>
#include <algorithm.h>
int main() {
printf("hello, world!\n");
return 0;
}
But when I run emcc test.c -o test.html I get the following error:
fatal error: 'algorithm.h' file not found
When I remove the line that imports algorithm.h the code compiles perfectly.
Why is this happening? I was under the impression that algorithm.h was part of the standard library.
Edit:
I changed the name of the file from test.c to test.cpp, I updated the header names to <cstdio> and <algorithms>, and I also set -std=c++11 and it works now.

If this is C++ use
#include <cstdio>
in place of stdio.h and
#include <algorithm>
instead

In standard C++ there is no <algorithm.h> - there is only <algorithm>
Also in C++ the stdio header is both accessible from <cstdio> and <stdio.h> for compatibility.
Also since you are including algorithm the file extension should be .cc or .cpp and not .c or else emcc/gcc will treat it as a C source instead of a C++ one.

When I submit it online, they always says compile errors

That's my code:
It works good on my mac.
But I'm not sure is that the problem of Gcc version or not.
they said the sstream and string header are wrong.
1779655.134485/Main.c:8:19: fatal error: sstream: No such file or directory
compilation terminated.
here is the hint
#include <iostream>
#include <sstream>
#include <string>
using namespace std;

You are trying to include C++ header file in your C program.
Gcc is C compiler.
You need to rename Main.c to Main.cpp and use g++ compiler...

C++ cout gives undeclared identifier

So, I have this question. Why does cout throws
error C2065: 'cout' : undeclared identifier
I am using Visual Studio 2012 as an IDE and I am writing a school project. I have everything done except an example file. So I am trying to write something on the screen like this:
#include "iostream"
#include "stdafx.h"
using namespace std;
int main()
{
cout<<"example";
return 0;
}
So the problem is with cout... printf works fine, but I want to use cout.
EDIT:
I've changed "" to <> but it is not helping. Also I am using this code only for example... This is not the whole project.

stdafx.h shall be the first include directive in your source file.
Switch files and convert the second include to <>, as other suggested.
#include "stdafx.h"
#include <iostream>
See this post for more information.

First of all:
#include <iostream>
instead of #include "iostream"
Secondly, it is generally considered bad practice to write using namespace std;, even though most courses start with that. It is better to only use what you actually need, in your case:
using std::cout;

#include "iostream"
should be
#include <iostream>
Quoting from this post:difference-between-iostream-and-iostream-quotes-in-include
By courtesy of #Jerry Coffin's answer:
When you use < >, the compiler only looks in the system-designated directory/directories (e.g., whatever you've set in the include environment variable) for the header.
When you use " ", the compiler looks in the local directory first, and if that fails, re-searches just like you'd used < >. Technically, (i.e., according to the standard) that doesn't have to be the "local" directory, but that's how it works in essentially every compiler of which I'm aware).
EDIT:
However, the root cause is that stdafx.h is a precompiled header. Visual C++ will not compile anything before the #include "stdafx.h" in the source file, unless the compile option /Yu'stdafx.h' is unchecked (by default); it assumes all code in the source up to and including that line is already compiled. However, it is still better to use <> with iostream not to confuse reader of the code.

If you use #include <iostream> with the <> instead of "" then it should work. Right now, the compiler doesn't know where to find the iostream library.
Also, you might want to change cout<<"example"; to cout<<"example"<<endl; for a new line so that it formats correctly.

Came across this issue while trying to build a Dynamic Linked Library. Make sure that instead of the #include stdafx.h you specify the following include on the first line of your .cpp file:
#include "pch.h"
This should also be the case for VS2017 or earlier.

This error also occurred in the Visual Studio 2017 IDE. Moving stdafx.h to the top solved the error.
For more on stdafx.h, see What's the use for "stdafx.h" in Visual Studio?