RtlFindUnicodePrefix function (ntifs.h)
The RtlFindUnicodePrefix routine searches for the best match for a given Unicode file name in a prefix table.
Syntax
NTSYSAPI PUNICODE_PREFIX_TABLE_ENTRY RtlFindUnicodePrefix(
[in] PUNICODE_PREFIX_TABLE PrefixTable,
[in] PCUNICODE_STRING FullName,
[in] ULONG CaseInsensitiveIndex
);
Parameters
[in] PrefixTable
Pointer to the prefix table. The table must have been initialized by calling RtlInitializeUnicodePrefix.
[in] FullName
Pointer to a Unicode string containing the full pathname for a file.
[in] CaseInsensitiveIndex
Position in the file name and prefix strings at which the comparison is to become case-insensitive. The string comparison is case-sensitive for the first CaseInsensitiveIndex characters in each string, case-insensitive for the remainder of the string.
| Value | Meaning |
|---|---|
| 0 | String comparison is case-insensitive. |
| 1..FullName.Length-1 | String comparison is case-sensitive for characters at positions 0 through CaseInsensitiveIndex-1, case-insensitive for characters from position CaseInsensitiveIndex to the end of the string. |
| FullName.Length | String comparison is case-sensitive. |
Return value
RtlFindUnicodePrefix returns a pointer to the longest proper prefix found for the given string at FullName. If no matching prefix is found, RtlFindUnicodePrefix returns NULL.
Remarks
Each prefix entry in the table is a pathname relative to the root directory of a file system volume. To be well-formed, the prefix must begin with a single backslash ().
When it finds a matching prefix, RtlFindUnicodePrefix rebalances the prefix table's splay tree.
File systems must call RtlInitializeUnicodePrefix to initialize the prefix table before using any other Rtl..UnicodePrefix routines on it. The initialized prefix table structure should be considered opaque.
Callers of the Rtl..UnicodePrefix routines are responsible for synchronizing access to the prefix table. A fast mutex is the most efficient synchronization mechanism to use for this purpose.
For information about other string-handling routines, see Run-Time Library (RTL) Routines.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows XP |
| Minimum supported server | Windows Server 2003 |
| Target Platform | Universal |
| Header | ntifs.h (include Ntifs.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | PASSIVE_LEVEL |