A.1 Thread Analyzer User APIs

If your code includes user-defined synchronizations, insert user APIs supported by the Thread Analyzer into the program to identify those synchronizations. This identification allows the Thread Analyzer to recognize the synchronizations and reduce the number of false positives. The Thread Analyzer user APIs are defined in libtha.so and are listed below.

Table A-1 Thread Analyzer User APIs

A C/C++ version and a Fortran version of the APIs are provided. Each API call takes a single argument id, whose value should uniquely identify the synchronization object.

In the C/C++ version of the APIs, the type of the argument is uintptr_t, which is 4 bytes long in 32-bit mode and 8 bytes long in 64-bit mode. You need to add #include <tha_interface.h> to your C/C++ source file when calling any of the APIs.

In the Fortran version of the APIs, the type of the argument is integer of kind tha_sobj_kind which is 8-bytes long in both 32-bit and 64–bit mode. You need to add #include "tha_finterface.h" to your Fortran source file when calling any of the APIs.

To uniquely identify a synchronization object, the argument id should have a different value for each different synchronization object. One way to do this is to use the value of the address of the synchronization object as the id. The following code example shows how to use the API to avoid a false positive data race.

Example A-1 Example Using Thread Analyzer APIs to Avoid False Positive Data Races

# include <tha_interface.h>
...
/* Initially, the ready_flag value is zero */
...
/* Thread 1: Producer */
100   data = ...
101   pthread_mutex_lock (&mutex);
      tha_notify_sync_post_begin ((uintptr_t) &ready_flag);
102   ready_flag = 1;
      tha_notify_sync_post_end ((uintptr_t) &ready_flag);

103   pthread_cond_signal (&cond);
104   pthread_mutex_unlock (&mutex);
 
 
/* Thread 2: Consumer */
200   pthread_mutex_lock (&mutex);
      tha_notify_sync_wait_begin ((uintptr_t) &ready_flag);
201   while (!ready_flag) {
202       pthread_cond_wait (&cond, &mutex);   
203   }
      tha_notify_sync_wait_end ((uintptr_t) &ready_flag);
204   pthread_mutex_unlock (&mutex);
205   ... = data;

For more information on the user APIs, see the libtha(3) man page.