如何解决收听 vala 中的后台进程
我想在后台收听一个命令 Process.spawn_command_line_async
是我想要的,但我不知道如何收听响应。当某些内容需要更新时,该命令将输出行,然后我需要解析该行并相应地运行一个函数。该进程在停止之前不会结束,因此需要在它运行时进行监听。
解决方法
您想要的是Process.spawn_commandline_async_with_pipes ()
。瓦拉多克has a code example:
private static bool process_line (IOChannel channel,IOCondition condition,string stream_name) {
if (condition == IOCondition.HUP) {
print ("%s: The fd has been closed.\n",stream_name);
return false;
}
try {
string line;
channel.read_line (out line,null,null);
print ("%s: %s",stream_name,line);
} catch (IOChannelError e) {
print ("%s: IOChannelError: %s\n",e.message);
return false;
} catch (ConvertError e) {
print ("%s: ConvertError: %s\n",e.message);
return false;
}
return true;
}
public static int main (string[] args) {
MainLoop loop = new MainLoop ();
try {
string[] spawn_args = {"ls","-l","-h"};
string[] spawn_env = Environ.get ();
Pid child_pid;
int standard_input;
int standard_output;
int standard_error;
Process.spawn_async_with_pipes ("/",spawn_args,spawn_env,SpawnFlags.SEARCH_PATH | SpawnFlags.DO_NOT_REAP_CHILD,out child_pid,out standard_input,out standard_output,out standard_error);
// stdout:
IOChannel output = new IOChannel.unix_new (standard_output);
output.add_watch (IOCondition.IN | IOCondition.HUP,(channel,condition) => {
return process_line (channel,condition,"stdout");
});
// stderr:
IOChannel error = new IOChannel.unix_new (standard_error);
error.add_watch (IOCondition.IN | IOCondition.HUP,"stderr");
});
ChildWatch.add (child_pid,(pid,status) => {
// Triggered when the child indicated by child_pid exits
Process.close_pid (pid);
loop.quit ();
});
loop.run ();
} catch (SpawnError e) {
print ("Error: %s\n",e.message);
}
return 0;
}
valac --pkg glib-2.0 GLib.Process.spawn_async_with_pipes.vala
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