#ifndef _NTMMAPI_H
//
// Virtual memory
//
#if (PHNT_MODE != PHNT_MODE_KERNEL)

/**
 * The NtWriteVirtualMemory routine writes virtual memory to a process.
 *
 * \param ProcessHandle A handle to the process whose memory is to be written.
 * \param BaseAddress A pointer to the base address in the specified process to which to write.
 * \param Buffer A pointer to the buffer that contains the data to be written to the address space of the specified process.
 * \param NumberOfBytesToWrite The number of bytes to be written to the specified process.
 * \param NumberOfBytesWritten A pointer to a variable that receives the number of bytes transferred into the specified buffer.
 * \return NTSTATUS Successful or errant status.
 * \remarks The copy helper requires PROCESS_VM_WRITE for a nonzero transfer; an inaccessible
 * target can still prevent or shorten the copy. A zero-byte request skips process-handle lookup and reports zero
 * bytes written. Do not treat zero-byte success as proof of write access.
 */
_Kernel_entry_
NTSYSCALLAPI
NTSTATUS
NTAPI
NtWriteVirtualMemory(
    _In_ HANDLE ProcessHandle,
    _In_opt_ PVOID BaseAddress,
    _In_reads_bytes_(NumberOfBytesToWrite) PVOID Buffer,
    _In_ SIZE_T NumberOfBytesToWrite,
    _Out_opt_ PSIZE_T NumberOfBytesWritten
    );

#endif
#endif
View code on GitHub

#ifndef _NTZWAPI_H

_Kernel_entry_
NTSYSCALLAPI
NTSTATUS
NTAPI
ZwWriteVirtualMemory(
    _In_ HANDLE ProcessHandle,
    _In_opt_ PVOID BaseAddress,
    _In_reads_bytes_(NumberOfBytesToWrite) PVOID Buffer,
    _In_ SIZE_T NumberOfBytesToWrite,
    _Out_opt_ PSIZE_T NumberOfBytesWritten
    );

#endif
View code on GitHub