PR_NewThreadPrivateIndex 编辑

Returns a new index for a per-thread private data table and optionally associates a destructor with the data that will be assigned to the index.

Syntax

#include <prthread.h>

PRStatus PR_NewThreadPrivateIndex(
   /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PRUintn *newIndex,
   /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PRThreadPrivateDTOR destructor);

Parameters

PR_NewThreadPrivateIndex has the following parameters:

newIndex

On output, an index that is valid for all threads in the process. You use this index with /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_SetThreadPrivate and /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_GetThreadPrivate.

destructor

Specifies a destructor function /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PRThreadPrivateDTOR for the private data associated with the index. This function can be specified as NULL.

Returns

The function returns one of the following values:

• If successful, PR_SUCCESS.
• If the total number of indices exceeds 128, PR_FAILURE.

Description

If PR_NewThreadPrivateIndex is successful, every thread in the same process is capable of associating private data with the new index. Until the data for an index is actually set, the value of the private data at that index is NULL. You pass this index to /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_SetThreadPrivate and /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_GetThreadPrivate to set and retrieve data associated with the index.

When you allocate the index, you may also register a destructor function of type /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PRThreadPrivateDTOR. If a destructor function is registered with a new index, it will be called at one of two times, as long as the private data is not NULL:

• when replacement private data is set with /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_SetThreadPrivate
• when a thread exits

The index maintains independent data values for each binding thread. A thread can get access only to its own thread-specific data. There is no way to deallocate a private data index once it is allocated.