A thread routine is a function that runs in a separate thread from the main program and takes a single argument. In the first interface below, the argument is the address of a integer(4) variable. It will be accessed as an INTEGER(4) in the body of thread_proc because of the POINTER attribute.
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INTERFACE integer(4) FUNCTION thread_proc(arg) !DEC$ ATTRIBUTES STDCALL, ALIAS:"_thread_proc" :: thread_proc integer(4),POINTER :: arg END FUNCTION END INTERFACE |
In this second interface example, the argument is passed as an address of some undefined data in memory. You must create a pointer to a specific data type variable with the POINTER attribute and assign the lpThreadParameter argument to it in the body of the thread_proc routine. You can pass a pointer to an entire block of data with this method.
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INTERFACE integer(4) FUNCTION thread_proc(lpThreadParameter) !DEC$ ATTRIBUTES STDCALL, ALIAS:"_thread_proc" :: thread_proc integer(INT_PTR_KIND()) lpThreadParameter END FUNCTION END INTERFACE |
Example 1 |
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Program TESTPROC0 use ifcore use ifmt INTERFACE integer(4) FUNCTION Thread_Proc0(arg) !DEC$ ATTRIBUTES STDCALL, ALIAS:"_thread_proc0" :: Thread_Proc0 integer(4),POINTER :: arg END FUNCTION END INTERFACE integer(INT_PTR_KIND()) ThreadHandle integer(INT_PTR_KIND()), PARAMETER :: security = 0 integer(INT_PTR_KIND()), PARAMETER :: stack_size = 0 integer(INT_PTR_KIND()) :: thread_id integer(4) :: ivalue0 = 12345678 ThreadHandle = CreateThread(security,stack_size,Thread_Proc0,loc(ivalue0), & CREATE_SUSPENDED, thread_id ) iretlog = SetThreadPriority(ThreadHandle, THREAD_PRIORITY_BELOW_NORMAL ) iretint = ResumeThread(ThreadHandle) call sleepqq(100) ! let io complete end integer(4) function Thread_Proc0(arg) USE IFCORE USE IFMT !DEC$ ATTRIBUTES STDCALL, ALIAS:"_thread_proc0" :: Thread_Proc0 integer(4), POINTER :: arg write(6,*) "The value of the Thread_Proc0 argument is ",arg Thread_Proc0 = 0 call ExitThread(0) end function |
The resulting output will be similar to the following example:
The value of the Thread_Proc0 argument is 12345678
Example 2 |
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Program TESTPROC1 use ifcore use ifmt INTERFACE integer(4) FUNCTION Thread_Proc1(lpThreadParameter) !DEC$ ATTRIBUTES STDCALL,ALIAS:"_thread_proc1" :: Thread_Proc1 integer(INT_PTR_KIND()) lpThreadParameter END FUNCTION END INTERFACE integer(INT_PTR_KIND()) ThreadHandle1 integer(INT_PTR_KIND()), PARAMETER :: security = 0 integer(INT_PTR_KIND()), PARAMETER :: stack_size = 0 integer(INT_PTR_KIND()) :: thread_id integer(4) :: ivalue1(5) = (/1,2,3,4,5/) ThreadHandle1 = CreateThread(security,stack_size,Thread_Proc1,loc(ivalue1(1)), & CREATE_SUSPENDED, thread_id ) iretlog = SetThreadPriority(ThreadHandle1, THREAD_PRIORITY_BELOW_NORMAL ) iretint = ResumeThread(ThreadHandle1) call sleepqq(100) ! let IO complete end integer(4) function Thread_Proc1(lpThreadParameter) USE IFCORE USE IFMT !DEC$ ATTRIBUTES STDCALL, ALIAS:"_thread_proc1" :: Thread_Proc1 integer(INT_PTR_KIND()) lpThreadParameter integer(4) arg(5) POINTER(parg,arg) parg = lpThreadParameter write(6,*) "The value of the Thread_Proc1 argument is ",arg Thread_Proc1 = 0 call ExitThread(0) end function |
The resulting output will be similar to the following example:
The value of the Thread_Proc1 argument is 1 2 3 4 5