NtQuerySystemEnvironmentValue - NtDoc

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

// Environment values

NTSYSCALLAPI
NTSTATUS
NTAPI
NtQuerySystemEnvironmentValue(
    _In_ PUNICODE_STRING VariableName,
    _Out_writes_bytes_(ValueLength) PWSTR VariableValue,
    _In_ USHORT ValueLength,
    _Out_opt_ PUSHORT ReturnLength
    );

#endif
#endif

View code on GitHub
#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwQuerySystemEnvironmentValue(
    _In_ PUNICODE_STRING VariableName,
    _Out_writes_bytes_(ValueLength) PWSTR VariableValue,
    _In_ USHORT ValueLength,
    _Out_opt_ PUSHORT ReturnLength
    );

#endif

View code on GitHub

Seems not works on NT 4.0 SP6. Control Panel applet query and set System Environment values by Rtl...Environment functions or directly by registry.

Documented by

Requirements

Privilege: SE_SYSTEM_ENVIRONMENT_NAME

See also