try something like this (it is only a demonstration, not working code!)
key to solve problem you've encountered are
io_stdout = null;
io_stderr = null;
it unrefs io channel, and releases descriptors
private IOChannel io_stderr;
private IOChannel io_stdout;
private uint io_stderr_watch_id;
private uint io_stdout_watch_id;
private Pid child_pid;
private uint child_watch_id = 0;
private void run() {
int child_stdout;
int child_stderr;
Process.spawn_async_with_pipes(null, { command }, null,
SpawnFlags.SEARCH_PATH | SpawnFlags.DO_NOT_REAP_CHILD, null, out
child_pid, null, out child_stdout, out child_stderr);
io_stdout = new IOChannel.unix_new(child_stdout);
io_stderr = new IOChannel.unix_new(child_stderr);
io_stdout_watch_id = io_stdout.add_watch(IOCondition.IN,
on_stdout_read);
io_stderr_watch_id = io_stderr.add_watch(IOCondition.IN,
on_stderr_read);
child_watch_id = ChildWatch.add(child_pid, on_child_exits);
}
private void on_child_exits(Pid pid, int status) {
Process.close_pid(pid);
GLib.Source.remove(io_stdout_watch_id);
GLib.Source.remove(io_stderr_watch_id);
try {
io_stdout.shutdown(true);
} catch(IOChannelError e) {
warning(@"Error \"$(e.message)\" during shutting down
stdout pipe to the child process");
}
try {
io_stderr.shutdown(true);
} catch(IOChannelError e) {
warning(@"Error \"$(e.message)\" during shutting down
stderr pipe to the child process");
}
io_stdout = null;
io_stderr = null;
cancel_child_watch();
}
private string? on_read(IOChannel source) {
string line;
try {
IOStatus ret = source.read_line(out line, null, null);
switch(ret) {
case IOStatus.ERROR:
warning("Read error");
kill();
return null;
case IOStatus.EOF:
message("End of File");
return null;
}
} catch(IOChannelError e) {
warning(@"I/O error: $(e.message)");
kill();
return null;
} catch(ConvertError e) {
warning(@"Convert error: $(e.message)");
return null;
}
return line;
}
private bool on_stderr_read(IOChannel source, IOCondition condition) {
var line = on_read(source);
if(line != null) {
do_something(line);
}
return true;
}
private bool on_stdout_read(IOChannel source, IOCondition condition) {
var line = on_read(source);
if(line != null) {
do_something(line);
}
return true;
}
2012/9/24 tomw <[email protected]>:
> ok, here's a bit more meat. Hopefully this help to tackle the issue:
>
> currently I'm using Vala 0.17.6. Obviously some files are left open as
> the open file count is increasing (checking with lsof | wc -l ) until I
> get the span error:
>
> Error spawning Uptime process - Failed to create pipe for communicating
> with child process (Too many open files)
>
> thanks,
>
>
>
> /* pipetest.vala
> * valac --pkg gio-2.0 --pkg posix pipetest.vala
> */
>
> using GLib;
>
>
> public class Pipetest.Main : Object {
> public MainLoop main_loop;
> public int counter = 0;
>
>
> public Main () {
> main_loop = new GLib.MainLoop (null, false);
> }
>
>
>
> public void run () {
> Timeout.add_seconds (1, get_uptime);
> }
>
> public bool get_uptime () {
> string uptime = "";
> int [] pipefd = {0, 0};
>
>
> if (Posix.pipe(pipefd) < 0) {
> debug ("Error - unable to open pipe");
> }
>
> Posix.close(pipefd[1]); //closing the write end of pipe
> try {
> string[] runme = {"/usr/bin/uptime"};
> int input;
> int output;
> int error;
> Pid child_pid;
> bool res = Process.spawn_async_with_pipes (null,
> runme,
> null,
>
> SpawnFlags.DO_NOT_REAP_CHILD,
> null,
> out
> child_pid,
> out input,
> out
> pipefd[0],
> out error
> );
>
> var filestream = FileStream.fdopen (pipefd[0], "r");
> uptime = filestream.read_line ();
> if (res) {
> int child_status = 0;
> int ret_waitpid = Posix.waitpid (child_pid,
> out child_status, 0);
> if (ret_waitpid < 0 ) {
> debug ("Waitpid returned error code :
> %d", ret_waitpid);
> }
>
> Posix.close (pipefd[0]);
> Process.close_pid (child_pid);
>
> }
> } catch (SpawnError e) {
> debug ("Error spawning Uptime process - %s",
> e.message);
> }
>
> debug ("%d : Uptime : %s", counter, uptime);
> counter++;
>
> return true;
> }
>
>
> static int main (string[] args) {
> var main = new Main ();
> main.run ();
> main.main_loop.run ();
> return 0;
> }
>
> }
>
> --
> tomw <[email protected]>
>
> _______________________________________________
> vala-list mailing list
> [email protected]
> https://mail.gnome.org/mailman/listinfo/vala-list
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