TlsSetValue function
Applies to: desktop apps only
Stores a value in the calling thread's thread local storage (TLS) slot for the specified TLS index. Each thread of a process has its own slot for each TLS index.
Syntax
BOOL WINAPI TlsSetValue( __in DWORD dwTlsIndex, __in_opt LPVOID lpTlsValue );
Parameters
- dwTlsIndex [in]
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The TLS index that was allocated by the TlsAlloc function.
- lpTlsValue [in, optional]
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The value to be stored in the calling thread's TLS slot for the index.
Return value
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
Remarks
TLS indexes are typically allocated by the TlsAlloc function during process or DLL initialization. When a TLS index is allocated, its storage slots are initialized to NULL. After a TLS index is allocated, each thread of the process can use it to access its own TLS slot for that index. A thread specifies a TLS index in a call to TlsSetValue, to store a value in its slot. The thread specifies the same index in a subsequent call to TlsGetValue, to retrieve the stored value.
TlsSetValue was implemented with speed as the primary goal. The function performs minimal parameter validation and error checking. In particular, it succeeds if dwTlsIndex is in the range 0 through (TLS_MINIMUM_AVAILABLE – 1). It is up to the programmer to ensure that the index is valid before calling TlsGetValue.
Examples
For an example, see Using Thread Local Storage or Using Thread Local Storage in a Dynamic-Link Library.
Requirements
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Minimum supported client | Windows XP |
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Minimum supported server | Windows Server 2003 |
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See also
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Build date: 3/7/2012
