[This is preliminary documentation and subject to change.]
The WriteProcessMemoryVlm function writes memory in a specified process. The entire area to be written to must be accessible, or the operation fails.
BOOL WriteProcessMemoryVlm(
HANDLE hProcess, // handle to process whose memory is written to
PVOID64 lpBaseAddress,
// address to start writing to
PVOID64 lpBuffer, // pointer to buffer to write data to
DWORD nSize, // number of bytes to write
LPDWORD lpNumberOfBytesWritten
// actual number of bytes written
);
The address specified is 64 bits and can therefore be used to access memory in the process allocated using VirtualAllocVlm, or the address can be a sign-extended 32-bit address.
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError. The function fails if the requested write operation crosses into an area of the process that is inaccessible.
WriteProcessMemoryVlm copies the data from the specified buffer in the current process to the address range of the specified process. Any process that has a handle with PROCESS_VM_WRITE and PROCESS_VM_OPERATION access to the process to be written to can call WriteProcessMemoryVlm. The process whose address space is being written to is typically, but not necessarily, being debugged.
Before any data transfer occurs, the system verifies that all memory at the given base address for the specified size is accessible for write access. If the memory is not accessible for writing, no writing is done and WriteProcessMemoryVlm fails.
Note To guard against an access violation, use structured exception handling to protect any code that writes to or reads from a memory-mapped view. For more information on structured exception handling, see Reading and Writing.
Windows NT: Requires version 5.0 or later.
Windows: Unsupported.
Windows CE: Unsupported.
Header: Declared in winbase.h.
Import Library: Use kernel32.lib.
Memory Management Overview, Memory Management Functions, Very Large Memory (VLM), OpenProcess, ReadProcessMemoryVlm, VirtualAllocVlm