NtOpenProcess - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers 
#ifndef _NTPSAPI_H
// Processes
#if (PHNT_MODE != PHNT_MODE_KERNEL)

NTSYSCALLAPI
NTSTATUS
NTAPI
NtOpenProcess(
    _Out_ PHANDLE ProcessHandle,
    _In_ ACCESS_MASK DesiredAccess,
    _In_ POBJECT_ATTRIBUTES ObjectAttributes,
    _In_opt_ PCLIENT_ID ClientId
    );

#endif
#endif

View code on GitHub
#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwOpenProcess(
    _Out_ PHANDLE ProcessHandle,
    _In_ ACCESS_MASK DesiredAccess,
    _In_ POBJECT_ATTRIBUTES ObjectAttributes,
    _In_opt_ PCLIENT_ID ClientId
    );

#endif

View code on GitHub

This function is documented in Windows Driver Kit here and here.

AccessMask

ObjectAttributes

For standard processes, all fields of ObjectAttributes should be NULL.

ClientId

Process id and thread id must be fill with valid values.

Documented by

See also

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