try this

include/fls/io/mmap.hpp

@@ -7,9 +7,6 @@
 namespace fastlanes {
 class Mmap {
 public:
-	static std::byte* Open(bsz_t bsz, int& fd, const std::filesystem::path& path);
-	template <typename T>
-	static T*         Open(bsz_t bsz, int& fd, const std::filesystem::path& path);
 	static std::byte* Resize(bsz_t bsz, int& fd);
 	template <typename T>
 	static T*   Resize(bsz_t bsz, int& fd);

src/io/mmap.cpp

@@ -12,36 +12,6 @@
 #include <unistd.h>
 
 namespace fastlanes {
-/*
- *
- * */
-std::byte* Mmap::Open(bsz_t init_bsz, int& fd, const std::filesystem::path& path) {
-	/**/
-#if defined(_WIN32)
-	// Use _open() on Windows
-	fd = open(path.c_str(), _O_RDWR | _O_CREAT, _S_IREAD | _S_IWRITE);
-#else
-	// Use POSIX open() on Linux/macOS
-	fd = open(path.c_str(), O_RDWR | O_CREAT, 0777);
-#endif
-
-	if (fd == -1) {
-		/**/
-		throw std::runtime_error(strerror(errno));
-	}
-
-	struct stat file_info {};
-	if (stat(path.c_str(), &file_info) == -1) { throw std::runtime_error("stat"); }
-
-	if (file_info.st_size == 0) {
-		if (ftruncate(fd, static_cast<off_t>(init_bsz)) == -1) { throw std::runtime_error("Error resizing the file"); }
-		if (stat(path.c_str(), &file_info) == -1) { throw std::runtime_error("stat"); }
-	}
-
-	auto* p = reinterpret_cast<std::byte*>(
-	    mmap(nullptr, static_cast<size_t>(file_info.st_size), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0));
-	return p;
-}
 
 void Mmap::Close(void* p, bsz_t bsz, int& fd) {
 	/**/
@@ -60,12 +30,6 @@ T* Mmap::Resize(bsz_t bsz, int& fd) {
 	return reinterpret_cast<T*>(Resize(bsz, fd));
 }
 
-template <typename T>
-T* Mmap::Open(bsz_t bsz, int& fd, const std::filesystem::path& path) {
-	return reinterpret_cast<T*>(Open(bsz, fd, path));
-}
-
-template int64_t*  Mmap::Open<>(bsz_t bsz, int& fd, const std::filesystem::path& path);
 template uint64_t* Mmap::Resize<>(bsz_t bsz, int& fd);
 
 } // namespace fastlanes