IoGetTopLevelIrp function (wdm.h)
The IoGetTopLevelIrp routine returns the value of the TopLevelIrp field of the current thread.
Syntax
PIRP IoGetTopLevelIrp();
Return value
IoGetTopLevelIrp returns the value of the TopLevelIrp field of the current thread.
Remarks
IoGetTopLevelIrp can return NULL, an arbitrary file-system-specific value (such as a pointer to the current IRP), or one of the flags listed in the following table.
If the current thread holds no resources above the file system, IoGetTopLevelIrp returns NULL.
If the file system is the top-level component for the current thread, IoGetTopLevelIrp returns a pointer to the current IRP.
If a component other than the file system is the top-level component for the current thread, IoGetTopLevelIrp returns one of the following flags:
| Flag | Meaning |
|---|---|
| FSRTL_FSP_TOP_LEVEL_IRP | This is a recursive call. |
| FSRTL_CACHE_TOP_LEVEL_IRP | The cache manager is the top-level component for the current thread. |
| FSRTL_MOD_WRITE_TOP_LEVEL_IRP | The modified page writer is the top-level component for the current thread. |
| FSRTL_FAST_IO_TOP_LEVEL_IRP | The cache manager is the top-level component for the current thread, and the current thread is in a fast I/O path. |
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Universal |
| Header | wdm.h (include Ntifs.h, Wdm.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | <= DISPATCH_LEVEL |