SYNOPSIS
#include <hal.h>
int hal_init_funct_to_thread(const char *funct_name, const char *thread_name, int position);ARGUMENTS
- funct_name
-
The name of the function.
- thread_name
-
The name of the thread.
- position
-
The desired location within the thread. This determines the init order of the running the functions in the thread at startup. A positive number indicates the desired location as measured from the beginning of the thread. A negative number indicated the desired location as measured from the end. A value of +1 means this function will become the first one to run, +5 means it will be the fifth one to run. A value of -2 means it will be next to last, and -1 means it will be last. Zero (0) is an illegal position value.
DESCRIPTION
The hal_init_funct_to_thread() function registers funcname to run exactly once in the realtime context of thread_name.
Init functions run before the thread executes any cyclic (addf-registered) function.
The init list is invoked in a dedicated "special cycle" the first time the thread observes threads_running == 1.
The cyclic function list is skipped during that cycle.
After the init list returns, the thread’s period is re-anchored.
The next cyclic cycle wakes one full period later.
This avoids both spurious "unexpected realtime delay" and assures a clean starting boundary for long/slow init functions.
Calls made to hal_init_funct_to_thread() after the init cycle has already run fail with -EALREADY.
RETURN VALUE
Returns zero (0) on success. Returns a negative errno code on failure:
| -EPERM |
HAL is config locked. |
| -EINVAL |
An invalid argument was passed. |
| -EFAULT |
The shared memory was not mapped. |
| -ENOENT |
The function or thread does not exist. |
| -EALREADY |
if the thread is already running. |
| -ENOMEM |
Failed to allocate memory for function registration. |
REALTIME CONSIDERATIONS
Call only from realtime init code, not from other realtime or non-realtime code.
SEE ALSO
hal_add_funct_to_thread(3), hal_thread_new(3), hal_export_funct(3)