yail

Yet Another Injection Library — a Windows x64 manual-map DLL injection library written in modern C++23.

Features

• x64 PE manual mapping (no LoadLibrary traces)
• Static TLS support
• Exception handling (SEH/VEH compatible)
• Heap validation compatibility with UCRT
• Inject by process ID or process name
• Load from file path or raw bytes in memory
• Returns std::expected<uintptr_t, std::string> — no exceptions, clear error messages

Requirements

• Windows x64
• C++23 compiler (MSVC recommended)
• CMake 3.28+
• vcpkg

Building

cmake --preset windows-debug
cmake --build cmake-build/build/windows-debug

To also build the examples:

cmake --preset windows-debug -DYAIL_BUILD_EXAMPLES=ON
cmake --build cmake-build/build/windows-debug

Usage

Inject into a process by name

#include <yail/yail.hpp>

auto result = yail::manual_map_injection_from_file("my.dll", "target.exe");

if (!result)
    std::println("Failed: {}", result.error());
else
    std::println("Loaded at 0x{:x}", result.value());

Inject into a process by PID

auto result = yail::manual_map_injection_from_file("my.dll", GetCurrentProcessId());

Inject from raw bytes

std::vector<uint8_t> dll_bytes = /* ... */;
auto result = yail::manual_map_injection_from_raw(dll_bytes, "target.exe");

CMake Integration

After installing, consume yail in your project:

find_package(yail CONFIG REQUIRED)
target_link_libraries(my_target PRIVATE yail::yail)

API

namespace yail
{
    // Inject from a file path
    std::expected<uintptr_t, std::string>
    manual_map_injection_from_file(std::string_view dll_path, std::uintptr_t process_id);

    std::expected<uintptr_t, std::string>
    manual_map_injection_from_file(std::string_view dll_path, std::string_view process_name);

    // Inject from raw bytes
    std::expected<uintptr_t, std::string>
    manual_map_injection_from_raw(const std::span<std::uint8_t>& raw_dll, std::uintptr_t process_id);

    std::expected<uintptr_t, std::string>
    manual_map_injection_from_raw(const std::span<std::uint8_t>& raw_dll, std::string_view process_name);
}

On success, returns the base address of the mapped image in the target process. On failure, returns a string describing the error.

License

Zlib