NAME CreateTask -- Create task with given name, priority, stacksize SYNOPSIS task = CreateTask(name,pri,initPC,stackSize) struct Task *CreateTask(STRPTR,LONG,funcEntry,ULONG); FUNCTION This function simplifies program creation of sub-tasks by dynamically allocating and initializing required structures and stack space, and adding the task to Exec's task list with the given name and priority. A tc_MemEntry list is provided so that all stack and structure memory allocated by CreateTask() is automatically deallocated when the task is removed. An Exec task may not call dos.library functions or any function which might cause the loading of a disk-resident library, device, or file (since such functions are indirectly calls to dos.library). Only AmigaDOS Processes may call AmigaDOS; see the dos.library/CreateProc() or the dos.library/CreateNewProc() functions for more information. If other tasks or processes will need to find this task by name, provide a complex and unique name to avoid conflicts. If your compiler provides automatic insertion of stack-checking code, you may need to disable this feature when compiling sub-task code since the stack for the subtask is at a dynamically allocated location. If your compiler requires 68000 registers to contain particular values for base relative addressing, you may need to save these registers from your main process, and restore them in your initial subtask code. The function entry initPC is generally provided as follows: In C: extern void functionName(); char *tname = "unique name"; task = CreateTask(tname, 0L, functionName, 4000L); In assembler: PEA startLabel INPUTS name - a null-terminated name string pri - an Exec task priority between -128 and 127, normally 0 funcEntry - the address of the first executable instruction of the subtask code stackSize - size in bytes of stack for the subtask. Don't cut it too close - system function stack usage may change. RESULT task - a pointer to the newly created task, or NULL if there was not enough memory. BUGS Under exec.library V37 or beyond, the AddTask() function used internally by CreateTask() can fail whereas it couldn't fail in previous versions of Exec. Prior to amiga.lib V37.14, this function did not check for failure of AddTask() and thus might return a pointer to a task structure even though the task was not actually added to the system. SEE ALSO DeleteTask(), exec/FindTask()
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