CoIncrementMTAUsage function (combaseapi.h)

Keeps MTA support active when no MTA threads are running.

Syntax

HRESULT CoIncrementMTAUsage(
  [out] CO_MTA_USAGE_COOKIE *pCookie
);

Parameters

[out] pCookie

Address of a PVOID variable that receives the cookie for the CoDecrementMTAUsage function, or NULL if the call fails.

Return value

If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

The CoIncrementMTAUsage function enables clients to create MTA workers and wait on them for completion before exiting the process.

The CoIncrementMTAUsage function ensures that the system doesn't free resources related to MTA support., even if the MTA thread count goes to 0.

On success, call the CoDecrementMTAUsage once only. On failure, don't call the CoDecrementMTAUsage function.

Don't call CoIncrementMTAUsage during process shutdown or inside dllmain. You can call CoIncrementMTAUsage before the call to start the shutdown process.

You can call CoIncrementMTAUsage from one thread and CoDecrementMTAUsage from another as long as a cookie previously returned by CoIncrementMTAUsage is passed to CoDecrementMTAUsage.

CoIncrementMTAUsage creates the MTA, if the MTA does not already exist. CoIncrementMTAUsage puts the current thread into the MTA, if the current thread is not already in an apartment

You can use CoIncrementMTAUsage when:

• You want a server to keep the MTA alive even when all worker threads are idle.
• Your API implementation requires COM to be initialized, but has no information about whether the current thread is already in an apartment, and does not need the current thread to go into a particular apartment.

Requirements

Requirement	Value
Target Platform	Windows
Header	combaseapi.h
Library	Ole32.lib
DLL	Ole32.dll

See also

CoDecrementMTAUsage