FSH SEMREQUEST: Difference between revisions
Created page with "This function allows an FSD to obtain exclusive access to a semaphore. ==Syntax== FSH_SEMREQUEST(pSem, cmsTimeout) ==Parameters== ;pSem: is the handle to the system semaph..." |
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This function allows an FSD to obtain exclusive access to a semaphore. | This function allows an FSD to obtain exclusive access to a semaphore. | ||
==Syntax== | ==Syntax== | ||
FSH_SEMREQUEST(pSem, cmsTimeout) | FSH_SEMREQUEST(pSem, cmsTimeout) | ||
==Parameters== | ==Parameters== | ||
;pSem: is the handle to the system semaphore or the long address of the ram semaphore. | ;pSem: is the handle to the system semaphore or the long address of the ram semaphore. | ||
;cmsTimeout: is the number of milliseconds to wait. | |||
==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_INTERRUPT the current thread received a signal. | |||
*ERROR_INTERRUPT the current thread received a signal. | *ERROR_SEM_TIMEOUT the time-out expired without gaining access to the semaphore. | ||
*ERROR_SEM_OWNER_DIED the owner of the semaphore died. | |||
*ERROR_TOO_MANY_SEM_REQUESTS there are too many semaphore requests in progress. | |||
*ERROR_PROTECTION_VIOLATION the semaphore is inaccessible. | |||
==Calling Sequence== | ==Calling Sequence== | ||
<PRE> | <PRE> | ||
| Line 25: | Line 23: | ||
unsigned long cmsTimeout; | unsigned long cmsTimeout; | ||
</PRE> | </PRE> | ||
==Remarks== | ==Remarks== | ||
The time-out value of 0xFFFFFFFF indicates an indefinite time-out. | The time-out value of 0xFFFFFFFF indicates an indefinite time-out. | ||
The caller may receive access to the semaphore after the time-out period has expired without receiving an ERROR_SEM_TIMEOUT. Semaphore time-out values, therefore, should not be used for exact timing and sequencing. | The caller may receive access to the semaphore after the time-out period has expired without receiving an ERROR_SEM_TIMEOUT. Semaphore time-out values, therefore, should not be used for exact timing and sequencing. | ||
FSH_SEMREQUEST may block. | FSH_SEMREQUEST may block. | ||
;Note: | ;Note: OS/2 does not validate input parameters. An FSD, therefore, should call FSH_PROBEBUF where appropriate. | ||
[[Category:IFS Interfaces]] | [[Category:IFS Interfaces]] | ||
{{DISPLAYTITLE:FSH_SEMREQUEST}} | {{DISPLAYTITLE:FSH_SEMREQUEST}} | ||
Latest revision as of 05:44, 20 February 2020
This function allows an FSD to obtain exclusive access to a semaphore.
Syntax
FSH_SEMREQUEST(pSem, cmsTimeout)
Parameters
- pSem
- is the handle to the system semaphore or the long address of the ram semaphore.
- cmsTimeout
- is the number of milliseconds to wait.
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_INTERRUPT the current thread received a signal.
- ERROR_SEM_TIMEOUT the time-out expired without gaining access to the semaphore.
- ERROR_SEM_OWNER_DIED the owner of the semaphore died.
- ERROR_TOO_MANY_SEM_REQUESTS there are too many semaphore requests in progress.
- ERROR_PROTECTION_VIOLATION the semaphore is inaccessible.
Calling Sequence
int far pascal FSH_SEMREQUEST(pSem, cmsTimeout) void far * pSem; unsigned long cmsTimeout;
Remarks
The time-out value of 0xFFFFFFFF indicates an indefinite time-out.
The caller may receive access to the semaphore after the time-out period has expired without receiving an ERROR_SEM_TIMEOUT. Semaphore time-out values, therefore, should not be used for exact timing and sequencing.
FSH_SEMREQUEST may block.
- Note
- OS/2 does not validate input parameters. An FSD, therefore, should call FSH_PROBEBUF where appropriate.