qnx_spawn_process
qnx_spawn_process — is an implementation of the C function qnx_spawn.
Syntax
qnx_spawn_process (exec, node, priority, scheduler,
flags, program, arg_list, file_list, ctfile)
Arguments
- exec
- If
non-nil, then
execute the process, otherwise spawn a separate
task.
- node
- The node on which to spawn, or zero for the current node.
- priority
- The scheduler priority of the new task.
- scheduler
- the scheduler algorithm for the new task.
- flags
- The spawn flags.
- program
- The program name.
- arg_list
- Arguments to the program, as a list, excluding the program name.
- file_list
- A list of up to 10 files to be associated with
the first 10 file descriptors of the new process. If any
element in the list is a non-file, then use the corresponding
file descriptor in the current process. A nil file-list
indicates that all 10 file descriptors will be inherited from
the calling task.
- ctfile
- A file associated with the controlling terminal for the new process.
Returns
The task ID of the new task, or -1 if an error occurs, and the errno is set.
Description
This is an implementation of the qnx_spawn
C function. It is currently only available in QNX 4. This is
the lowest level function for creating a new process.
Passing -1 to the priority option will cause the new task
to inherit its priority from the parent, otherwise a value
from 1-31 is acceptable.
Passing -1 to the scheduler option will cause the new task
to inherit its scheduler activities from the parent,
otherwise the following flags are defined for the
scheduler option:
- SCHED_FIFO First-in, First-Out scheduling algorithm.
- SCHED_RR Round-robin scheduling algorithm.
- SCHED_OTHER Adaptive scheduling.
The following spawn flags are defined for the flags option:
- _SPAWN_BGROUND The process will be started with SIGINT and SIGQUIT ignored.
- _SPAWN_DEBUG The process will be started with the single step flag set. Rarely used.
- _SPAWN_HOLD The process will be started in a STOPPED state.
- _SPAWN_NEWPGRP The new process will start a new process group.
- _SPAWN_NOHUP The process will be started with SIGHUP ignored
- _SPAWN_NOZOMBIE When the new process terminates it will not become a zombie waiting for its father to do a wait on its death. The parent process will not see the child process die and a SIGCHILD will not be set.
- _SPAWN_SETSID The new process will start a new session.
- _SPAWN_SIGCLR The new process will not inherit ignored signals from its parent.
- _SPAWN_TCSETPGRP The new process will start a new terminal group. ALL keyboard breaks will be directed a it.
- _SPAWN_XCACHE Instruct the file system to place the executable in cache in hopes that it will be loaded again soon.
The library "const/QNXOS" should be required to use these constants
Errors that can happen when using this function:
- E2BIG The sum of the
bytes used by the new process image's argument
list and environment is too
big.
- EACCES No permissions to
execute
program.
- EAGAIN No free process
entries or local
memory.
- EINVAL The priority or the scheduling policy is invalid.
- ENAMETOOLONG The length
of the program name, expanded to it's full
path, is too
long.
- ENOENT The program does
not exist.
- ENOEXEC The program is
not the correct format (not an
executable).
- ENOLIC Insufficient
licenses to use this
function.
- ENOMEM Not enough system
memory.
- ENONDP The program needs
an 80x87. A co-processor is not installed and
the emulator (emu87) is not
running.
- ETXTBUSY The program to
launch is open for write
(busy).
The ctfile is a file descriptor associated with the new process. This parameter is only meaningful if the _SPAWN_SETID flag is set. If you wish to start a new session without a controlling terminal then pass -1.
Example
Examples of this function are beyond the scope of this documentation.
