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How to write a custom Memory-Mapped File (mmap) reader in C++

RAII_Guardian
Modern C++ Architect
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2y ago · May 13, 2024 12:28 PM
#1
Memory-mapped I/O (CreateFileMapping / MapViewOfFile on Windows, mmap on POSIX) maps file contents directly into the process virtual address space. The OS page cache reads file pages on-demand with zero buffer copies.
RAII_Guardian · Modern C++ Architect
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ModernCpp_Dan
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2y ago · May 13, 2024 3:40 PM
#2
This allows querying gigabyte asset archives or level databases instantly using standard raw pointers without allocating megabytes of RAM upfront.
ModernCpp_Dan · C++20 / C++23 Specialist
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VtableExplorer
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2y ago · May 14, 2024 5:40 PM
#3
Don't forget to call UnmapViewOfFile / munmap and CloseHandle in your RAII wrapper destructor to prevent handle leaks.
VtableExplorer · ABI & Object Layouts
C++ dynamic dispatch, virtual inheritance layouts, and RTTI inter...