Ruby Console access from C extension

tomasz

I am trying to write directly from a Ruby C++ extension to the Ruby Console through a

std;;cout << "Text\n";

and/or

prinf("Text\n");

, but have no luck. Nothing shows up in the RC.
Is not Ruby extension standard output redirected to the Ruby Console?

I guess I can still try invoking from C++ Ruby method SKETCHUP_CONSOLE.write("Text\n) described in this thread:
, but maybe there is a way to redirect std:cout to the Ruby Console.

Dan Rathbun

The Sketchup::Console does weird things to std I/O.

I would say that you need to create a extern "C" { } block, and try to use one of the C Ruby functions.

/* Your C++ code */

#ifdef __cplusplus
extern "C"{
#endif

// C code in here
VALUE
function tomaz_puts_to_con(str)
    VALUE str;
{
    int argc;
    VALUE *argv;
    VALUE out;
    out = rb_stdout;
    argc = 1;
    argv[0] = rb_str_new2(str)
    rb_io_puts(argc, argv, out)
}

#ifdef __cplusplus
}
#endif

if puts() does not work, try write() (...that happens on the Ruby side.)

/* Your C++ code */

#ifdef __cplusplus
extern "C"{
#endif

// C code in here
VALUE
function tomaz_write_to_con(str)
    VALUE str;
{
    VALUE out;
    out = rb_stdout;
    // io_write will convert str to ruby T_STRING
    io_write(out, str);
}

#ifdef __cplusplus
}
#endif

Dan Rathbun

EDIT: note that rb_eval_string(); is slow.

And I think you can also do:


/* Your C++ code */

  str = "$stdout.write('some message')\n"
  tomaz_write_to_con(str)

#ifdef __cplusplus
extern "C"{
#endif
 
// C code in here
VALUE
function tomaz_write_to_con(str)
    VALUE str;
{
    rb_eval_string(str);
}

#ifdef __cplusplus
}
#endif

or perhaps right from C++:

rb_eval_string("$stdout.write('some message')\n");

tbd

I used OutputDebugString and DbgView to view the messages and never had a problem compared with random crashes in Ruby world due stack overwriting.

you can also create a singleton wrapper if you want to log from Ruby world without going to the slow ruby console.

thomthom

@unknownuser said:

I used OutputDebugString and DbgView to view the messages

Ditto. But is there a OSX alternative?

tbd

system this command:

logger "this is my message in the console.app All Messages"

thomthom

@unknownuser said:

system this command:

logger "this is my message in the console.app All Messages"

Thankyou!

Dan Rathbun

@thomthom said:

@unknownuser said:

I used OutputDebugString and DbgView to view the messages

Ditto. But is there a OSX alternative?

There is the "Log Navigator":
https://developer.apple.com/library/mac/#recipes/xcode_help-log_navigator/_index.html

Dan Rathbun

@unknownuser said:

system this command:

logger "this is my message in the console.app All Messages"

See docs:

EDIT(2018-09-17): The old way of calling system('logger','my log message') seems to have been replaced with a unified system wide logging platform.

See: https://developer.apple.com/documentation/os/logging

tomasz

I have tried the last solution:

rb_eval_string("$stdout.write(\"Message\n\")");

and it works well. I am using it for debugging purpose, so the speed is not important for me.

Thanks!