elapsed time microseconds c++

[ignacio...@gmail.com]

hello,

I tried several ways ( clock(), gettimeofday()..) but I can get the proper way to measure the elapsed time in microseconds.

I am using eclipse to program in ansi c. Could anybody help me about how to measure the elapsed time in microsecond? Could it be possible to enclosed the code that I should use? 

thank you so much and sorry for the inconveniences

Regards

[Nuno Sucena Almeida]

Hi,
use a search engine and look for "linux measure time nanoseconds".
Also: man clock_gettime

regards,
Nuno

--
http://aeminium.org/nuno/

[Nuno Sucena Almeida]

On 09/26/2013 09:31 PM, Nuno Sucena Almeida wrote:
>
> Hi,
> use a search engine and look for "linux measure time nanoseconds".
> Also: man clock_gettime
>
> regards,
> Nuno
>

If you have C++11 , look for chrono, it might be easier
http://en.cppreference.com/w/cpp/chrono

[Dieter Wirz]

On Thu, Sep 26, 2013 at 9:36 PM, <ignacio...@gmail.com> wrote:
> hello,
>
> I tried several ways ( clock(), gettimeofday()..) but I can get the proper
> way to measure the elapsed time in microseconds.
>
> I am using eclipse to program in ansi c. Could anybody help me about how to
> measure the elapsed time in microsecond? Could it be possible to enclosed
> the code that I should use?

Ansi C or C++ (as in the title)?
In Ansi C it might look like this:

#include <sys/time.h>
#include <stdio.h>
// compile with: gcc -Wall gettimeofday.c -o gettimeofday
void main()
{
float elapsed_time;
struct timeval start_time, end_time;
gettimeofday( &start_time, NULL );
for (;;){
gettimeofday( &end_time, NULL );
elapsed_time = end_time.tv_sec - start_time.tv_sec + (
end_time.tv_usec - start_time.tv_usec ) / 1e6;
printf( "sec: %g \r", elapsed_time );
}
}

[ignacio...@gmail.com]

hi, Sorry for disturbing you. How can I compile  "gcc -Wall gettimeofday.c -o gettimeofday " in eclipse?

I got some errors:

Field "tv_sec" could not be resolved

Field "tv_usec" could not be resolved

symbol "cout" could not be resolved

symbol "endl" could not be resolved

symbol "std" could not be resolved

Sorry for the inconveniences 

Regards

[ignacio...@gmail.com]

On Tuesday, October 1, 2013 9:38:07 PM UTC+2, ignacio...@gmail.com wrote:

On Tuesday, October 1, 2013 2:11:39 PM UTC+2, Dieter Wirz wrote:

On Thu, Sep 26, 2013 at 9:36 PM,  <ignacio...@gmail.com> wrote:
> hello,
>
> I tried several ways ( clock(), gettimeofday()..) but I can get the proper
> way to measure the elapsed time in microseconds.
>
> I am using eclipse to program in ansi c. Could anybody help me about how to
> measure the elapsed time in microsecond? Could it be possible to enclosed
> the code that I should use?
Ansi C or C++ (as in the title)?
In Ansi C it might look like this:

#include <sys/time.h>
#include <stdio.h>
// compile with: gcc -Wall gettimeofday.c -o gettimeofday
void main()
{
    float elapsed_time;
    struct timeval start_time, end_time;
    gettimeofday( &start_time, NULL );
    for (;;){
        gettimeofday( &end_time, NULL );
        elapsed_time = end_time.tv_sec - start_time.tv_sec + (
end_time.tv_usec - start_time.tv_usec ) / 1e6;
        printf( "sec: %g          \r", elapsed_time );
        }
}

hi, Sorry for disturbing you. How can I compile  "gcc -Wall gettimeofday.c -o gettimeofday " in eclipse under ubuntu?

[ignacio...@gmail.com]

[Dieter Wirz]

On Tue, Oct 1, 2013 at 11:14 PM, <ignacio...@gmail.com> wrote:
>>> hi, Sorry for disturbing you. How can I compile "gcc -Wall
>>> gettimeofday.c -o gettimeofday " in eclipse under ubuntu?

I don't know Eclipse too much, I compile such programs in terminal:
Open Terminal
cd to the folder where gettimeofday.c is
type in:

gcc -Wall gettimeofday.c -o gettimeofday

run the Porgram with
./gettimeofday

>>> I got some errors:
>>> Field "tv_sec" could not be resolved
>>> Field "tv_usec" could not be resolved

Maybe you have to tell Eclipse:
- it is C (not C++)
- from where to include <sys/time.h>

HTH

[Tux Leonard]

The code works fine. Even with Eclipse.

How is it posible that you get errors about cout, endl and std. Those commands are not in the posted code.

2013/10/2 Dieter Wirz <didi...@gmail.com>

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[ignacio...@gmail.com]

Hi,

sorry it was my fault. I only have problems with:

>>> Field "tv_sec" could not be resolved
>>> Field "tv_usec" could not be resolved

the issue is that i can not find gettimeofday.c in ubuntu. I only find /usr/share/man/man2/gettimeofday.2.gz

sorry, i am quite new with this. how could i solve this issue?

Thank you so much

[Dieter Wirz]

On Thu, Oct 3, 2013 at 9:56 PM, <ignacio...@gmail.com> wrote:

> the issue is that i can not find gettimeofday.c in ubuntu. I only find

You have to save the code I provided as gettimeofday.c.....

However, I do not see what this has to do with BB(B). Do you want to
crosscompile with eclipse, or what are you intending to do???

[ignacio...@gmail.com]

My aim is program in ansi c my beaglebone black. I am using an ubuntu vm under mac os.

I am new in ubuntu and eclipse and this is the main problem, i guess :-S

I have a model that i would like to run into BB but i have problems to measure the elapsed time, i tried before with clock(), but looks like it doesn't measure properly the time. For this i am trying with gettimeofday, but i have the problems that i commented previously.

Looks like if eclipse could not link time.h and for this appear these errors. But maybe i am wrong

Really thanks to everybody for your help

[Tux Leonard]

Could you provide us your source, the compiler/linker output and your compile command?

2013/10/4 <ignacio...@gmail.com>

[Dieter Wirz]

Hi Ignacio

Eclipse with an installed crosscompiler is only one way to go and it
certainly makes sense if you have a huge Project with thousands of
lines of code, X, etc. But I usually code only small terminal programs
(in ANSI C) that read in some ports, write to some ports, do some
calculations and write the results to a excel readable text file. For
such problems I am too lazy to install Eclipse with all the gnuaebi
etc. stuff....
So, I edit and compile my programs directly on BB, usually over ssh
and sftp (usually from my Mac, with Cyberduck). The only thing you
need on BB is gcc and if you have a bit bigger projects make.

Starting with "Hello World" is always a good idea....
Connect to your BB with ssh
nano helloworld.c
type in your code, quit and save with "ctrl x"
gcc -Wall helloworld.c -o helloworld
And run your program with
./helloworld
you need the ./ for running terminal programs in the same folder....

Have fun!

[ignacio...@gmail.com]

Hi,

My big code compiles properly in eclipse. As you said I started with hello world and small codes. My problems became only measuring elapsed time. With small codes, just to measure elapsed time it still doesn't work. I tried with clock() as i said but the elapsed time showed in the terminal is wrong. Now I am trying with the code supplied by you, because i would like to try with gettimeofday but errors commented before.

I will put my compiler, linker and assembler later. I am not in my personal computer now.

really thanks for your help.

[ignacio...@gmail.com]

hi,

Looks like there is something wrong in eclipse. I compiled the code gettimeofday directly from ubuntu terminal and it works properly. Also the code works in my beaglebone :-)

BUT... :-S. I am trying to run my code. It compiles and run under ubuntu but when i try to run in in my beaglebone i got the error:

-sh: ./hil: cannot execute binary file

I am using the following command in my beaglebone:

chmod ugo+x hil

./hil

I am using this includes:

stdio.h

stdlib.h

math.h

sys/time.h

any suggestion? thanks in advance to everybody

[Tux Leonard]

Did you use a crosscompiler? 

You can also compile your code on your beaglebone.

2013/10/5 <ignacio...@gmail.com>

--

[Dave Hylands]

Hi,

On Sat, Oct 5, 2013 at 2:31 AM, <ignacio...@gmail.com> wrote:
>
> hi,
>
> Looks like there is something wrong in eclipse. I compiled the code gettimeofday directly from ubuntu terminal and it works properly. Also the code works in my beaglebone :-)
>
> BUT... :-S. I am trying to run my code. It compiles and run under ubuntu but when i try to run in in my beaglebone i got the error:
> -sh: ./hil: cannot execute binary file
>
> I am using the following command in my beaglebone:
> chmod ugo+x hil
> ./hil
>
> I am using this includes:
> stdio.h
> stdlib.h
> math.h
> sys/time.h
>
> any suggestion? thanks in advance to everybody

Try using the "file" command on your program. It will tell whether you built an ARM executable or an x86 executable. x86 executables will produce the error you're seeing when you try to run them on the beagleboard (since the beagleboard uses an ARM processor).

file ./hil

For example: file /bin/ls on my x86 ubuntu machine shows:

--
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com

[Dave Hylands]

Whoops - finger troubles....

/bin/ls: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0x37cdd635587f519989044055623abff939002027, stripped

and file run on an executable for the beagleboad will typically show something like:

bash: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.16, not stripped

So as Tux mentioned, you're probably using the host compiler instead of the cross compiler to build your program.