STRING - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _PHNT_NTDEF_H
#ifndef _NTDEF_

// Strings

typedef struct _STRING
{
    USHORT Length;
    USHORT MaximumLength;
    _Field_size_bytes_part_opt_(MaximumLength, Length) PCHAR Buffer;
} STRING, *PSTRING, ANSI_STRING, *PANSI_STRING, OEM_STRING, *POEM_STRING;

#endif
#endif

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This structure is documented in Windows Driver Kit and in Windows SDK.