C++ - No matching member function for call to 'push_back' - c++

Question

I am currently working on a college assignment and right now I'm struggling with vectors.
I am supposed to return a unique ID for an object and then add that object to a vector.
The object is a struct defined as follows:
struct VertexPuller{
std::vector<InVertex> head_settings;
std::vector<IndexType> indexing;
};
and the vector I am trying to push to is:
std::vector<std::unique_ptr<VertexPuller>> vertex_puller_tables;
The function I wrote looks like this:
auto vertex_puller= std::make_unique<VertexPuller>;
auto vp_id = reinterpret_cast<VertexPullerID>(vertex_puller);
vertex_puller_tables.push_back(std::move(vertex_puller));
return vp_id;
However at the second-to-last line, when i try to push the vertex puller into the vector, I get the error - No matching member function for call to 'push_back'.
I've been stuck on this for quite some time and i have no idea what may cause this, probably pointers, as usual with C and me.
Thanks for the suggestions!

Answer 1

The method push_back is there. The type that you send probably doesn't match. Try to read the compilation error and figure out what type was expected and what was the actual type that was sent.
A more simple example with same error:
int main() {
std::vector<int> vec;
vec.push_back("hey");
}
Compilation error is:
error: no matching function for call to `push_back`
However, if we read further it says:
main.cpp:6:24: error: no matching function for call to 'push_back(const char [4])'
6 | vec.push_back("hey");
| ^
In file included from /usr/local/include/c++/9.2.0/vector:67,
from main.cpp:2:
/usr/local/include/c++/9.2.0/bits/stl_vector.h:1184:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = int; _Alloc = std::allocator<int>; std::vector<_Tp, _Alloc>::value_type = int]' <near match>
1184 | push_back(const value_type& __x)
| ^~~~~~~~~
/usr/local/include/c++/9.2.0/bits/stl_vector.h:1184:7: note: conversion of argument 1 would be ill-formed:
main.cpp:6:19: error: invalid conversion from 'const char*' to 'std::vector<int>::value_type' {aka 'int'} [-fpermissive]
6 | vec.push_back("hey");
| ^~~~~
| |
| const char*
In file included from /usr/local/include/c++/9.2.0/vector:67,
from main.cpp:2:
/usr/local/include/c++/9.2.0/bits/stl_vector.h:1200:7: note: candidate: 'void std::vector<_Tp, _Alloc>::push_back(std::vector<_Tp, _Alloc>::value_type&&) [with _Tp = int; _Alloc = std::allocator<int>; std::vector<_Tp, _Alloc>::value_type = int]' <near match>
1200 | push_back(value_type&& __x)
| ^~~~~~~~~
/usr/local/include/c++/9.2.0/bits/stl_vector.h:1200:7: note: conversion of argument 1 would be ill-formed:
main.cpp:6:19: error: invalid conversion from 'const char*' to 'std::vector<int>::value_type' {aka 'int'} [-fpermissive]
6 | vec.push_back("hey");
| ^~~~~
| |
| const char*

Answer 2

vertex_puller is a std::make_unique<VertexPuller> function. It's not a unique_ptr<VertexPuller>. You have to call the function and pass any parameters you would pass to a VertexPuller constructor.
auto vertex_puller= std::make_unique<VertexPuller>(); // note the parentheses