storing a unique_ptr<> in a std::map

bssmap.cc

// gcc -g -Wall bssmap.cc -lstdc++ -std=c++20 -o bssmap
#include <cstring>

#include <iostream>
#include <memory>
#include <map>
#include <string>

//
// simple demo shim of the C struct BSS
extern "C" {

#define MAX_BSS_STR 32
struct BSS {
	char bssid_str[MAX_BSS_STR + 1];
};

struct BSS *bss_new(const char *bssid_str) {
	struct BSS *bss = (struct BSS*)calloc(1, sizeof(struct BSS));
	strncpy(bss->bssid_str, bssid_str, MAX_BSS_STR);
	printf("%s bss=%p\n", __func__, bss);
	return bss;
}

void bss_free(struct BSS **p_bss) {
	free(*p_bss);
	*p_bss = nullptr;
}

}  // end extern "C"

// 
// end of shim

// forward declaration for unique_ptr<> Deleter
void release_bss(struct BSS *);

// https://en.cppreference.com/w/cpp/memory/unique_ptr
using unique_bss_t = std::unique_ptr<struct BSS, decltype(&release_bss)>;

// key: the bssid as printable string
// value: safe container holding the C data structure
std::map<std::string, unique_bss_t> bss_db;

void release_bss(struct BSS *ptr )
{
	std::cout << __func__ << " ptr=" << reinterpret_cast<void *>(ptr) << "\n";
	bss_free(&ptr);
	// ptr == nullptr at this point
}

// how to store into the map so that a new BSS will release the previous 
int main()
{
	// actual BSS comes from decoding a complex linux netlink(7) nl80211 data
	// structure 
	struct BSS *bss;
	bss = bss_new("004068112233");

	std::string s { bss->bssid_str };
	unique_bss_t ubss { bss, &release_bss };

//	bss_db[ s ] = std::move(ubss);
//	bss_db[ s ] = ubss;
//	bss_db[ s ] = { bss, &release_bss };

//	auto p = std::make_pair(s,ubss);


	// TODO add more bss*
	//bss = bss_new("004068aabbcc");
	//bss = bss_new("004068112233");  // replace existing
}

Using GCC from the cli, I get an enormous template error.

CLion (clang-tidy) is giving me a simple error around the variations I've been trying lines 63-65.
In template: no matching constructor for initialization of 'std::unique_ptr<BSS, void (*)(BSS *)>'

Solution from someone on a discord channel: https://godbo.lt/z/fz8z4YqWP

"you cannot use bss_db[ s ] = { bss, &release_bss }; because the unique_bss_t is not default constructible. for that map has emplace: bss_db.emplace(s, std::move(ubss)); "