DosFreeThreadLocalMemory
From EDM2
Frees a block of thread-local memory that was originally allocated using DosAllocThreadLocalMemory.
Syntax
DosFreeThreadLocalMemory (p)
Parameters
- p (ULONG *) - input
- Address of the memory block to free.
Return Code
- rc (APIRET) - returns
- This function returns one of the following values:
- 0 NO_ERROR
- 87 ERROR_INVALID_PARAMETER
Remarks
When a process is started, a small block of memory is set aside to be used as a thread-local memory area. This memory is at the same virtual address for each thread, but is backed by different physical memory. This permits each thread to have a small block of memory that is unique, or local, to that thread.
The thread-local memory area consists of 32 DWORDs (128 bytes), each DWORD being 32-bits in size.
Example Code
This example shows how to allocate and free 3 DWORDs of local thread memory.
#define INCL_DOSPROCESS #define INCL_DOSERRORS #include <os2.h> #include <stdio.h> /* Needed for printf */ PULONG pulThreadDWords = NULL; /* Pointer to thread DWORDs returned */ APIRET rc = NO_ERROR; /* Return code */ int main(VOID) { /* Allocate 3 DWORDs of local thread memory */ rc = DosAllocThreadLocalMemory(3, /* Number of DWORDs */ &pulThreadDWords); /* Address returned */ if (rc != NO_ERROR) { printf("DosAllocThreadLocalMemory error: return code = %u\n", rc); return 1; } /* ... Use the thread-local memory ... */ rc = DosFreeThreadLocalMemory(pulThreadDWords); /* Free the DWORDs */ if (rc != NO_ERROR) { printf("DosFreeThreadLocalMemory error: return code = %u\n", rc); return 1; } return NO_ERROR; }