WriteProcessMemory
The WriteProcessMemory function writes data to an area of memory in a specified process. The entire area to be written to must be accessible, or the operation fails.
BOOL WriteProcessMemory(
HANDLE hProcess,
LPVOID lpBaseAddress,
LPCVOID lpBuffer,
SIZE_T nSize,
SIZE_T* lpNumberOfBytesWritten
);
Parameters
hProcess
[in]
Handle to the process whose memory is to be modified. The
handle must have PROCESS_VM_WRITE and PROCESS_VM_OPERATION
access to the process.
lpBaseAddress
[in] Pointer to the base address in the specified process to which data will be written. Before any data transfer occurs, the system verifies that all data in the base address and memory of the specified size is accessible for write
access. If this is the case, the function proceeds; otherwise, the function fails.
lpBuffer
[in] Pointer to the buffer that contains data to be written into the address space of the specified process.
nSize
[in] Number of bytes to be written to the specified process.
lpNumberOfBytesWritten
[out] Pointer to a variable that receives the number of bytes transferred into the specified process. This parameter is optional. If lpNumberOfBytesWritten is NULL, the parameter is ignored.
Return Values
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 will fail if the requested write operation crosses into an area of the process that is inaccessible.
Remarks
WriteProcessMemory 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 the function. The process whose address space is being written to is typically, but not necessarily, being debugged.
The entire area to be written to must be accessible. If it is not, the function fails as noted previously.
Requirements
Client: Included in Windows XP, Windows 2000 Professional, Windows NT Workstation, Windows Me, Windows 98, and Windows 95.
Server: Included in Windows Server 2003, Windows 2000 Server, and Windows NT Server.
Header: Declared in Winbase.h; include Windows.h.
Library: Use Kernel32.lib.