I'm trying to print a double argument in a DTrace script from a user defined probe. The probe is defined as such:
/**
* Fired when the garbage collection threshold is changed with a certain factor
* #param factor the factor with which the GC threshold is changed
*/
probe gc__threshold(double factor);
In my script I'm trying to print the argument as follows:
pony$target:::gc-threshold
{
print(args[0]);
}
However it gives me the following error:
dtrace: failed to compile script ./test.d: line 7: translator for args[0] from double to double is not defined
I'm running the script on a Mac. Due to the lack of documentation and no similar problem around on the internet I'm having trouble finding leads on how to solve this problem.
I've also tried using floats and long doubles, but the same error occurs.
Related
In a script I often call the function Rcplex(), which prints "CPLEX environment opened" and "Closed CPLEX environment" to the console. Since the function is called rather frequently, it prints this very often, which is quite annoying. Is there a way to suppress this? I tried sink(), suppressWarnings/Messages or invisible(catch.output()) but none of these did the trick. I proceeded to check the code of Rcplex() and found where the printing to the console happens. Rcplex() calls an underlying C-function (Rcplex.c). In the code of rcplex.c I located the commands which cause the printing:
REprintf("CPLEX environment opened\n");
REprintf("Closed CPLEX environment\n");
Is there a way to capture the output from REprintf() so that it does not get printed to the R-console? One way would obviously be to mess around with the Rcplex.c file and delete the corresponding lines. However, this would not be a very clean solution, which is why I'm asking for another way to capture the output from C-functions.
You had problems using sink() and capture.output() normally because sink() does not redirect output from REprintf, as we see in comments from the source code for REprintf:
/* =========
* Printing:
* =========
*
* All printing in R is done via the functions Rprintf and REprintf
* or their (v) versions Rvprintf and REvprintf.
* These routines work exactly like (v)printf(3). Rprintf writes to
* ``standard output''. It is redirected by the sink() function,
* and is suitable for ordinary output. REprintf writes to
* ``standard error'' and is useful for error messages and warnings.
* It is not redirected by sink().
However, we can use type = "message" to deal with this; from help("capture.output"):
Messages sent to stderr() (including those from message, warning and
stop) are captured by type = "message". Note that this can be "unsafe" and should only be used with care.
First I make a C++ function with the same behavior you're dealing with:
#include <Rcpp.h>
using namespace Rcpp;
// [[Rcpp::export]]
NumericVector example_function(NumericVector x) {
REprintf("CPLEX environment opened\n");
REprintf("Closed CPLEX environment\n");
// As mentioned by Dirk Eddelbuettel in the comments,
// Rcpp::Rcerr goes into the same REprintf() stream:
Rcerr << "Some more stuff\n";
return x;
}
If I call it from R normally, I get:
example_function(42)
CPLEX environment opened
Closed CPLEX environment
Some more stuff
[1] 42
However, I could instead do this:
invisible(capture.output(example_function(42), type = "message"))
[1] 42
And while the output is is printed to the console, the message is not.
Warning
I would be remiss if I didn't mention the warning from the help file I quoted above:
Note that this can be "unsafe" and should only be used with care.
The reason is that this will eliminate all output from actual errors as well. Consider the following:
> log("A")
Error in log("A") : non-numeric argument to mathematical function
> invisible(capture.output(log("A"), type = "message"))
>
You may or may not want to therefore send the captured output to a text file in case you have to diagnose something that went wrong. For example:
invisible(capture.output(log("A"), type = "message", file = "example.txt"))
Then I don't have to see the message in the console, but if I need to check example.txt afterward, the message is there:
Error in log("A") : non-numeric argument to mathematical function
I ran perf with the parameter -x to print in machine readable format. The output is as follows:
1285831153,,instructions,1323535732,100.00
7332248,,branch-misses,1323535732,100.00
1316.587352,,cpu-clock,1316776510,100.00
1568113343,,cycles,1323535732,100.00
the first number is clear but then the values after the descriptions are not clear to me. Is the first one behind the description the runtime? Then why is it different? What does the 100.00 mean at the end of each line? It is not documented; I looked it up here: https://perf.wiki.kernel.org/index.php/Tutorial#Machine_readable_output
-x option of stat command is implemented in tools/perf/builtin-stat.c file as csv_output flag, and printing is static void printout function "(line 1061). Last values in the string are probably from:
print_noise(counter, noise);
print_running(run, ena);
With single run of target program (no -r 5 or -r 2 options - https://perf.wiki.kernel.org/index.php/Tutorial#Repeated_measurement) print_noise will not print anything. And print_running is printing the "run" argument twice, as value and as percentage of ena
static void print_running(u64 run, u64 ena)
{
if (csv_output) {
fprintf(stat_config.output, "%s%" PRIu64 "%s%.2f",
csv_sep,
run,
csv_sep,
ena ? 100.0 * run / ena : 100.0);
} else if (run != ena) {
fprintf(stat_config.output, " (%.2f%%)", 100.0 * run / ena);
}
}
You have run/ena = 1 (100.00%), so theses field have no useful information for you.
They are used in the case of event multiplexing (try perf stat -d or perf stat -dd; https://perf.wiki.kernel.org/index.php/Tutorial#multiplexing_and_scaling_events) when user ask perf to measure more event that can be enabled at same time (8 hardware events on intel with only 7 real hardware counting hardware units). Perf (perf_events subsystem of kernel) will enable some subsets of events and will change these subsets several times per second. Then run/ena will be proportional to the time share when this event was enabled, and run will probably show exact time amount when the event was counted. With normal human-readable perf stat this is marked when there is no [100%] for the event line; and the reported event count may be scaled (estimated) for the full running time of the program (inexact scaled).
I have a suite of scalatest tests that output information to the console using println as they run.
When I run the suite using the Eclipse Scala plug-in (using Run As ... / 3 ScalaTest - File from the context menu) there is additional output to the console about which tests pass and which fail. I guess this output is from the runner.
The problem is that the lines from my code and the lines from the runner are not interleaved sensibly. It's as if they are being printed from two different threads that aren't synchronized.
For example here is the output from a run
>>>>>>>>>>>>>Starting The parser should warn when the interface name at the end does not match >>>>>>>>>>>>>>>>>>
(interface Fred
interface Bob)
-----------------------------
File: <unknown> line: 2 column: 11 Name does not match.
----The AST after parsing-------------
[ IntfDeclNd( (), (), () ) ]
---------------------------------------
<<<<<<<<<<<<<Finished The parser should warn when the interface name at the end does not match <<<<<<<<<<<<<<<<<
>>>>>>>>>>>>>Starting The parser should parse a class with generic args >>>>>>>>>>>>>>>>>>
(class Fred{type a, type b extends B}() class)
- should parse multiline comment at end of file *** FAILED ***
Expected 0, but got 1 (TestsBase.scala:103)
- should fail on incomplete multiline comment
- should parse single line comments
- should allow a class name to be repeated at the end
- should warn when the class name at the end does not match
- should allow an interface name to be repeated at the end
- should warn when the interface name at the end does not match
----The AST after parsing-------------
The lines starting with "- should" or "Expected" come from the runner and you can see that a bunch of them are plunked in the middle of the output from one of my tests. Other output from the runner appears elsewhere, this isn't all of it.
My questions: Why is this happening? Is there some way to get the runner's output to coordinate with my output?
Most likely, the suites are running in parallel.
http://www.scalatest.org/user_guide/using_the_runner#executingSuitesInParallel
With the proliferation of multi-core architectures, and the often
parallelizable nature of tests, it is useful to be able to run tests
in parallel. [...]
The -P option may optionally be appended with a number (e.g. "-P10" --
no intervening space) to specify the number of threads to be created
in the thread pool. If no number (or 0) is specified, the number of
threads will be decided based on the number of processors available.
So basically pass -P1 to the runner. For eclipse, the place would possibly be the Arguments tab.
I'm trying to understand how to access and use the Bus system with custom S-Function Blocks. I built a very basic S-Function using the S-Function Builder which has no input and one Bus output. The Bus is a struct consisting only of one field of type double. This works just fine.
No I tried to connect its output to a newly created block (also with help of the S-Function Builder) which has one Bus input and no output. It should write the value of the only field inside the struct to the console using mexPrintf. But the value is always 0 (zero)
I set the output of the first block like that in the output wrapper function (works fine):
out0->data = 12;
and I try to get the input value inside the other block like this (prints always 0):
real_T insig = in0->data;
mexPrintf("Got a %d", insig);
Stupid error - I was using %d instead of %f for printing a double value...
I am trying to write an interface between RSPEC (ruby flavoured BDD) and a Windows application. The application itself is written in an obscure language, but it has a C API to provide access. I've gone with Ruby/DL but am having difficulties getting even the most basic call to a DLL method to work. Here is what I have so far, in a file called gt4r.rb:
require 'dl/import'
module Gt4r
extend DL::Importable
dlload 'c:\\gtdev\\r321\\bin\\gtvapi'
# GTD initialization/termination functions
extern 'int GTD_init(char *[], char *, char *)'
extern 'int GTD_initialize(char *, char *, char *)'
extern 'int GTD_done(void)'
extern 'int GTD_get_error_message(int, char **)'
end
My reading so far suggests that this is all I need to get going, so I wrote up a RSPEC example:
require 'gt4r'
##test_environment = "INCLUDE=C:\\graphtalk\\env\\aiadev\\config\\aiadev.ini"
##normal_user = "BMCHARGUE"
describe Gt4r do
it 'initializes' do
rv = Gt4r.gTD_initialize ##normal_user, ##normal_user, ##test_environment
rv.should == 0
end
end
And when run...
C:\code\GraphTalk>spec -fs -rgt4r gt4r_spec.rb
Gt4r
- initializes (FAILED - 1)
1)
'Gt4r initializes' FAILED
expected: 0,
got: 13 (using ==)
./gt4r_spec.rb:9:
Finished in 0.031 seconds
1 example, 1 failure
The return value (13) is an actual return code, meaning an error, but when I try to add the gTD_get_error_message call to my RSPEC, I can't get the parameters to work.
Am I heading in the right direction and can anyone point to the next thing I can try?
Thanks,
Brett
A follow up to this question, showing the part that fails when I try to get the error message from my target library:
require 'gt4r'
##test_environment = "INCLUDE=C:\\graphtalk\\env\\aiadev\\config\\aiadev.ini"
##normal_user = "BMCHARGUE"
describe Gt4r do
it 'initializes' do
rv = Gt4r.gTD_initialize ##normal_user, ##normal_user, ##test_environment
Gt4r.gTD_get_error_message rv, #msg
#msg.should == ""
rv.should == 0
end
end
I expect the error message to be returned in #msg, but when run I get the following:
Gt4r
(eval):5: [BUG] Segmentation fault
ruby 1.8.6 (2008-08-11) [i386-mswin32]
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
And this if I use a symbol (:msg) instead:
C:\code\GraphTalk\gt4r_dl>spec -fs -rgt4r gt4r_spec.rb
Gt4r
- initializes (ERROR - 1)
1)
NoMethodError in 'Gt4r initializes'
undefined method `to_ptr' for :msg:Symbol
(eval):5:in `call'
(eval):5:in `gTD_get_error_message'
./gt4r_spec.rb:9:
Finished in 0.046 seconds
1 example, 1 failure
Clearly I am missing something about passing parameters between ruby and C, but what?
The general consensus is you want to avoid DL as much as possible. The (english) documentation is quite sketchy and the interface is difficult to use for anything but trivial examples.
Ruby native C interface is MUCH easier to program against. Or you could use FFI, which fills a similiar niche to DL, originally comes from the rubinius project and has recently been ported to "normal" ruby. It has a nicer interface and is much less painful to use:
http://blog.headius.com/2008/10/ffi-for-ruby-now-available.html
The return value (13) is an actual
return code, meaning an error, but
when I try to add the
gTD_get_error_message call to my
RSPEC, I can't get the parameters to
work.
It might help posting the error instead of the code that worked :)
Basically, once you start having to deal with pointers as in (int, char **), things get ugly.
You need to allocate the data pointer for msg to be written to, since otherise C will have nowhere to write the error messages. Use DL.mallo.