pid_t __Dillo_fork(const int* ChildIO, unsigned Flags)
Basically a UNIX-like fork. You probably want to use
__Dillo_fork2() (see section __Dillo_fork2) or __Dillo_spawn()
(see section __Dillo_spawn) instead of this routine.
The caller may pass a pipes which will be used to communicate with the child process. -1 is used to indicate that the pipe's IO channel should not be employed. The pipe-ends are closed after forking. On fork failure all of the pipe ends are closed.
ChildIO is used to send and receive data with the child process;
ChildIO[0] is read by the child, ChildIO[1] is written to
by the child. Warning: this is not same as a what you would get
from pipe(), but rather from two calls to pipe().
ChildIO is dup'd to `stdin', `stdout', `stderr',
and then closed.
The child process has its SIGCHLD and SIGPIPE signals
set to exit the child process.
-1 on error, 0 if this is the child process, otherwise the process ID of the child if we are the parent.
__Dillo_fork2() (see section __Dillo_fork2),
__Dillo_spawn() (see section __Dillo_spawn)
Profiling reveals that this is intensely slow. Don't fork unless you need to. We are the child... set ourselves up to die cleanly in case ofclose(ChildIO[0]);
pid_t __Dillo_fork2(int* FileDes, unsigned Flags)
Basically a UNIX-like fork.
A short note on how the child processes' IO is setup.
The child process will write to its stdout IO channel.
If Flags as the DILLO_NEWIN flag set, a new pipe will be
created; the child process will read from its stdin IO channel.
Otherwise, it is not defined here what the child will read from.
FileDes is set for the parent to communicate with the child;
it is not set for the child process. FileDes[0] is used to read
the childs output; it is set to be non-blocking, and close on
exec().
If the DILLO_NEWIN flag is set, FileDes[1]
can be used to to send data to the child. Otherwise FileDes[1]
is set to a meaningless value.
If the DILLO_SHARE_ERR flag is set, the child's standard error
is dup'd to its standard output. Otherwise, its standard error
channel is the same as its parent.
If the DILLO_TTY flag is set, the child will be set to
communicate using a master/slave pseudo-tty instead of standard pipe.
The child process has its SIGCHLD and SIGPIPE signals
set to exit the child process.
-1 on error, 0 if this is the child process, otherwise the process ID of the child if we are the parent.
__Dillo_fork() (see section __Dillo_fork),
__Dillo_spawn() (see section __Dillo_spawn)
Profiling reveals that this is intensely slow. Don't fork unless you need to.
The child process may choose to fork again. This is done one linux
systems when the DILLO_TTY flag is used, as a part of the
mechanism to change controlling tty's.
pid_t __Dillo_spawn(int* filedes, char* const ArgV[], char* const env[], unsigned Flags)
This spawns and executes a program. Name is the path of the program. env is the environment that the program should use.
If the DILLO_NEWIN flag is set, FileDes[1]
can be used to to send data to the child. Otherwise FileDes[1]
is set to a meaningless value.
If the DILLO_SHARE_ERR flag is set, the child's standard error
is dup'd to its standard output. Otherwise, its standard error
channel is the same as its parent.
If the DILLO_TTY flag is set, the child will be set to
communicate using a master/slave pseudo-tty instead of standard pipe.
-1 on error, otherwise the process id of the spawned task.
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