The thread safe variable functions in the Utility Library can be a little difficult to use correctly because they are type-agnostic. So the Utility Library provides macros in utility.h that create type-safe helper functions to create and use thread safe variables. An example of thread safe scalar variables is shown in samples/utility/threading/threadsafevar/incrementvalue.c. Thread safe array variables are similar, except you do not have Get/Set helper functions - you have to use the GetPointer/ReleasePointer functions. Here is a simple example that hopefully helps illustrate how to create and use a thread-safe array variable:
#include <windows.h>
#include <utility.h>
#include <formatio.h>
#include <ansi_c.h>
/* Define a thread safe array variable called Buffer of type char[4] with nesting = 1 */
DefineThreadSafeArrayVar(char, Buffer, 4, 1);
int CVICALLBACK ThreadFunction(void * threadData)
{
int i, writer = threadData != NULL;
for (i = 0; i < 100; ++i)
{
/* Lock Buffer and get pointer to its first element */
char * buffer = GetPointerToBuffer();
if (writer)
{
int j;
/* Write some random data in Buffer */
for (j = 0; j < 4; ++j)
buffer[j] = 'a' + (rand() % 26);
}
else
{
/* Read and print the values in Buffer */
FmtOut("%s<%4c\n", buffer);
}
/* Unlock Buffer */
ReleasePointerToBuffer();
Sleep(100);
}
return 0;
}
void main(void)
{
int pool = 0;
/* Initialize Buffer */
InitializeBuffer();
/* Spawn two worker threads */
CmtNewThreadPool(2, &pool);
CmtScheduleThreadPoolFunction(pool, ThreadFunction, (void *) 1 /* writer */, NULL);
CmtScheduleThreadPoolFunction(pool, ThreadFunction, NULL /* reader */, NULL);
CmtDiscardThreadPool(pool);
/* Uninitialize Buffer */
UninitializeBuffer();
getchar();
}
