FSH FINDDUPHVPB: Difference between revisions
Created page with "This function provides the mechanism to identify a previous instance of a volume during the FS_MOUNT process. ==Syntax== FSH_FINDDUPHVPB(hVPB, phVPB) ==Parameters== ;hVP..." |
mNo edit summary |
||
| Line 1: | Line 1: | ||
This function provides the mechanism to identify a previous instance of a volume during the FS_MOUNT process. | {{DISPLAYTITLE:FSH_FINDDUPHVPB}} | ||
This function provides the mechanism to identify a previous instance of a volume during the FS_MOUNT process. | |||
==Syntax== | ==Syntax== | ||
FSH_FINDDUPHVPB(hVPB, phVPB) | FSH_FINDDUPHVPB(hVPB, phVPB) | ||
==Parameters== | ==Parameters== | ||
;hVPB: is the handle to the volume to be found. | ;hVPB: is the handle to the volume to be found. | ||
;phVPB: is the pointer to where the handle of matching volume will be stored. | |||
==Returns== | ==Returns== | ||
If no error is detected, a zero error code is returned. If an error is detected, one of the following error codes is returned: | If no error is detected, a zero error code is returned. If an error is detected, one of the following error codes is returned: | ||
*ERROR_NO_ITEMS :indicates there is no matching hVPB. | |||
==Calling Sequence== | ==Calling Sequence== | ||
<PRE> | <PRE> | ||
| Line 19: | Line 20: | ||
unsigned short far * phVPB; | unsigned short far * phVPB; | ||
</PRE> | </PRE> | ||
==Remarks== | ==Remarks== | ||
When OS/2 is recognizing a volume, it calls the FSD to mount the volume. At this point, the FSD may elect to allocate storage and buffer data for that volume. The mount process will allocate a new VPB whenever the media becomes uncertain, that is, when the device driver recognizes it can no longer be certain the media is unchanged. This VPB cannot be collapsed with a previously allocated VPB, because of a reinsertion of media, until the FS_MOUNT call returns. The previous VPB, however, may have some cached data that must be updated from the media (the media may have been written while it was removed) FSH_FINDDUPHVPB allows the FSD to find this previous occurrence of the volume in order to update the cached information for the old VPB. Remember the newly created VPB will be unmounted if there is another, older VPB for that volume. | When OS/2 is recognizing a volume, it calls the FSD to mount the volume. At this point, the FSD may elect to allocate storage and buffer data for that volume. The mount process will allocate a new VPB whenever the media becomes uncertain, that is, when the device driver recognizes it can no longer be certain the media is unchanged. This VPB cannot be collapsed with a previously allocated VPB, because of a reinsertion of media, until the FS_MOUNT call returns. The previous VPB, however, may have some cached data that must be updated from the media (the media may have been written while it was removed) FSH_FINDDUPHVPB allows the FSD to find this previous occurrence of the volume in order to update the cached information for the old VPB. Remember the newly created VPB will be unmounted if there is another, older VPB for that volume. | ||
;Note: OS/2 does not validate input parameters. An FSD, therefore, should call FSH_PROBEBUF where appropriate. | |||
[[Category:IFS Interfaces]] | [[Category:IFS Interfaces]] | ||
Latest revision as of 22:07, 12 February 2020
This function provides the mechanism to identify a previous instance of a volume during the FS_MOUNT process.
Syntax
FSH_FINDDUPHVPB(hVPB, phVPB)
Parameters
- hVPB
- is the handle to the volume to be found.
- phVPB
- is the pointer to where the handle of matching volume will be stored.
Returns
If no error is detected, a zero error code is returned. If an error is detected, one of the following error codes is returned:
- ERROR_NO_ITEMS :indicates there is no matching hVPB.
Calling Sequence
int far pascal FSH_FINDDUPHVPB(hVPB, phVPB) unsigned short hVPB; unsigned short far * phVPB;
Remarks
When OS/2 is recognizing a volume, it calls the FSD to mount the volume. At this point, the FSD may elect to allocate storage and buffer data for that volume. The mount process will allocate a new VPB whenever the media becomes uncertain, that is, when the device driver recognizes it can no longer be certain the media is unchanged. This VPB cannot be collapsed with a previously allocated VPB, because of a reinsertion of media, until the FS_MOUNT call returns. The previous VPB, however, may have some cached data that must be updated from the media (the media may have been written while it was removed) FSH_FINDDUPHVPB allows the FSD to find this previous occurrence of the volume in order to update the cached information for the old VPB. Remember the newly created VPB will be unmounted if there is another, older VPB for that volume.
- Note
- OS/2 does not validate input parameters. An FSD, therefore, should call FSH_PROBEBUF where appropriate.