[C / C++] Portable library to measure time

Discussion in 'C++' started by Julek, Nov 1, 2009.

  1. Julek

    Julek Guest

    Is there any simple library that can return a systemtime in a
    resolution of max. 10ms, working on both Windows XP and modern Linux?
    time() works on both but has a resolution of 1s. There is
    GetSystsmTime on Windows with 10ms resolution, there are probably also
    some functions for Linux - but maybe there is some library works on
    both these OSes?
    Julek, Nov 1, 2009
    #1
    1. Advertising

  2. Julek wrote:
    > Is there any simple library that can return a systemtime in a
    > resolution of max. 10ms, working on both Windows XP and modern Linux?


    Nothing can be better than the underlying OS unless you have a special
    way of going to the hardware that the OS doesn't do. So, dig into the
    OS APIs and find out.

    > time() works on both but has a resolution of 1s. There is
    > GetSystsmTime on Windows with 10ms resolution, there are probably also
    > some functions for Linux - but maybe there is some library works on
    > both these OSes?


    Maybe or maybe not. Why don't you write one?

    V
    --
    Please remove capital 'A's when replying by e-mail
    I do not respond to top-posted replies, please don't ask
    Victor Bazarov, Nov 1, 2009
    #2
    1. Advertising

  3. "Julek" <> wrote in message
    news:...
    > Is there any simple library that can return a systemtime in a
    > resolution of max. 10ms, working on both Windows XP and modern Linux?
    > time() works on both but has a resolution of 1s. There is
    > GetSystsmTime on Windows with 10ms resolution, there are probably also
    > some functions for Linux - but maybe there is some library works on
    > both these OSes?


    don't use a library for what you can trivially do yourself...
    using libs in this case does little more than create external dependencies
    for which any potential users of said code may be forced to deal with later.

    a lib is good if it is known to be commonly or near universally available,
    is already in use of a project, or represents a non-trivial amount of work,
    but otherwise I feel use of libs is ill-advised, as it may create
    portability issues (and people trying to dig around online to find "X
    obscure library no one has heard of", or figuring out how to do likewise by
    looking at the code and figuring out what the API calls do...)..


    now, maybe of some help:
    #ifdef linux
    ....
    gettimeofday(...);
    ....
    #endif

    or, maybe even:
    #if defined(linux) || defined(__BSD__) || defined (__MACOSX__) || ...
    ....
    gettimeofday(...);
    ....
    #endif



    my personal suggestion is to create a function, or maybe collection of them,
    which provide a consistent interface to OS-specific behaviors, and keep any
    OS specific parts confined to these functions.
    BGB / cr88192, Nov 1, 2009
    #3
  4. Julek

    Richard Guest

    [Please do not mail me a copy of your followup]

    Julek <> spake the secret code
    <> thusly:

    >Is there any simple library that can return a systemtime in a
    >resolution of max. 10ms, working on both Windows XP and modern Linux?
    >time() works on both but has a resolution of 1s. There is
    >GetSystsmTime on Windows with 10ms resolution, there are probably also
    >some functions for Linux - but maybe there is some library works on
    >both these OSes?


    See Boost.DateTime
    <http://www.boost.org/doc/libs/1_40_0/doc/html/date_time/posix_time.html>

    "Defines a non-adjusted time system with nano-second/micro-second
    resolution and stable calculation properties."

    --
    "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
    <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/>

    Legalize Adulthood! <http://legalizeadulthood.wordpress.com>
    Richard, Nov 1, 2009
    #4
  5. Julek

    Richard Guest

    [Please do not mail me a copy of your followup]

    "BGB / cr88192" <> spake the secret code
    <hckadt$h06$> thusly:

    >don't use a library for what you can trivially do yourself...
    >[...]
    >my personal suggestion is to create a function, or maybe collection of them,
    >which provide a consistent interface to OS-specific behaviors, and keep any
    >OS specific parts confined to these functions.


    In other words: reinvent someone else's library.
    --
    "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
    <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/>

    Legalize Adulthood! <http://legalizeadulthood.wordpress.com>
    Richard, Nov 1, 2009
    #5
  6. Julek

    James Kanze Guest

    Re: Portable library to measure time

    On Nov 1, 3:45 pm, "BGB / cr88192" <> wrote:
    > "Julek" <> wrote in message


    > news:...


    > > Is there any simple library that can return a systemtime in
    > > a resolution of max. 10ms, working on both Windows XP and
    > > modern Linux? time() works on both but has a resolution of
    > > 1s. There is GetSystsmTime on Windows with 10ms resolution,
    > > there are probably also some functions for Linux - but maybe
    > > there is some library works on both these OSes?


    > don't use a library for what you can trivially do yourself...


    That's ridiculous. You're job is to provide the best possible
    solution at the lowest possible cost. Reinventing something
    that is already available should only be done when there is a
    very good reason for not using what is available. (Copyright
    restrictions come to mind---some projects can't use GPL, for
    example.)

    > using libs in this case does little more than create external
    > dependencies for which any potential users of said code may be
    > forced to deal with later.


    If you're using a third party library, users never see it.

    > a lib is good if it is known to be commonly or near
    > universally available, is already in use of a project, or
    > represents a non-trivial amount of work, but otherwise I feel
    > use of libs is ill-advised, as it may create portability
    > issues (and people trying to dig around online to find "X
    > obscure library no one has heard of", or figuring out how to
    > do likewise by looking at the code and figuring out what the
    > API calls do...)..


    > now, maybe of some help:
    > #ifdef linux
    > ...
    > gettimeofday(...);
    > ...
    > #endif


    > or, maybe even:
    > #if defined(linux) || defined(__BSD__) || defined (__MACOSX__) || ...
    > ...
    > gettimeofday(...);
    > ...
    > #endif


    And you say that using a lib will create portability issues?
    What happens when you encounter a new OS? (And of course,
    conditional compilation can quickly make the code completely
    unreadable.)

    > my personal suggestion is to create a function, or maybe
    > collection of them, which provide a consistent interface to
    > OS-specific behaviors, and keep any OS specific parts confined
    > to these functions.


    In other words, write a library that someone else has already
    written.

    Sometimes it's necessary---there can be a number of reasons not
    to use an existing library. But you shouldn't rewrite it unless
    it is necessary for some reason.

    --
    James Kanze
    James Kanze, Nov 2, 2009
    #6
  7. Julek

    Dann Corbit Guest

    In article <90319dc1-1978-46f1-81f5-
    >, says...
    >
    > Is there any simple library that can return a systemtime in a
    > resolution of max. 10ms, working on both Windows XP and modern Linux?
    > time() works on both but has a resolution of 1s. There is
    > GetSystsmTime on Windows with 10ms resolution, there are probably also
    > some functions for Linux - but maybe there is some library works on
    > both these OSes?


    This is (undoubtably) the most famous portable time library:
    ftp://elsie.nci.nih.gov/pub/

    Here is Bernstein's libtai (be aware that Posix IGNORES leap seconds):
    http://cr.yp.to/libtai.html

    Here is a Windows flavored gettimeofday():

    #include <windows.h>
    /* FILETIME of Jan 1 1970 00:00:00. */
    static const unsigned long long epoch = 116444736000000000ULL;

    /*
    * timezone information is stored outside the kernel so tzp isn't used
    anymore.
    *
    * Note: this function is not for Win32 high precision timing purpose.
    See
    * elapsed_time().
    */
    int
    gettimeofday(struct timeval * tp, struct timezone * tzp)
    {
    FILETIME file_time;
    SYSTEMTIME system_time;
    ULARGE_INTEGER ularge;

    GetSystemTime(&system_time);
    SystemTimeToFileTime(&system_time, &file_time);
    ularge.LowPart = file_time.dwLowDateTime;
    ularge.HighPart = file_time.dwHighDateTime;

    tp->tv_sec = (long) ((ularge.QuadPart - epoch) / 10000000L);
    tp->tv_usec = (long) (system_time.wMilliseconds * 1000);

    return 0;
    }

    HTH
    Dann Corbit, Nov 3, 2009
    #7
  8. Julek

    Phil Carmody Guest

    (Richard) writes:
    > Reply-To: (Richard)


    > [Please do not mail me a copy of your followup]


    What's that header supposed to imply, then?

    Has surnameless Richard (you know, the one who posts drivel) morphed
    in the last week or so?

    Phil
    --
    Any true emperor never needs to wear clothes. -- Devany on r.a.s.f1
    Phil Carmody, Nov 4, 2009
    #8
  9. Phil Carmody <> writes:
    > (Richard) writes:
    >> Reply-To: (Richard)

    >
    >> [Please do not mail me a copy of your followup]

    >
    > What's that header supposed to imply, then?


    Perhaps it's added automatically by his news software.

    --
    Keith Thompson (The_Other_Keith) <http://www.ghoti.net/~kst>
    Nokia
    "We must do something. This is something. Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"
    Keith Thompson, Nov 4, 2009
    #9
  10. Re: Portable library to measure time

    On 2 Nov, 10:18, James Kanze <> wrote:
    > On Nov 1, 3:45 pm, "BGB / cr88192" <> wrote:
    > > "Julek" <> wrote in message
    > >news:....


    > > > Is there any simple library that can return a systemtime in
    > > > a resolution of max. 10ms, working on both Windows XP and
    > > > modern Linux?  time() works on both but has a resolution of
    > > > 1s. There is GetSystsmTime on Windows with 10ms resolution,
    > > > there are probably also some functions for Linux - but maybe
    > > > there is some library works on both these OSes?

    >
    > > don't use a library for what you can trivially do yourself...


    wrapper the 3rd party lib so different libraries present the same
    abstraction (interface) to the application code. Software Engineering
    101.

    > That's ridiculous.  You're job is to provide the best possible
    > solution at the lowest possible cost.  


    "lowest possible /lifetime/ cost"

    > Reinventing something
    > that is already available should only be done when there is a
    > very good reason for not using what is available.  (Copyright
    > restrictions come to mind---some projects can't use GPL, for
    > example.)


    as someone who is lumbered with some unsupported 3PLs there can be
    other reasons. Some 3PLs cost money. Sometimes a lot of money.

    > > using libs in this case does little more than create external
    > > dependencies for which any potential users of said code may be
    > > forced to deal with later.

    >
    > If you're using a third party library, users never see it.


    the poor bloody maintainer DOES though!


    > > a lib is good if it is known to be commonly or near
    > > universally available, is already in use of a project, or
    > > represents a non-trivial amount of work, but otherwise I feel
    > > use of libs is ill-advised, as it may create portability
    > > issues (and people trying to dig around online to find "X
    > > obscure library no one has heard of", or figuring out how to
    > > do likewise by looking at the code and figuring out what the
    > > API calls do...)..
    > > now, maybe of some help:

    >
    > > #ifdef linux
    > > ...


    puke. I hate ifdefs.


    > >     gettimeofday(...);
    > > ...
    > > #endif
    > > or, maybe even:
    > > #if defined(linux) || defined(__BSD__) || defined (__MACOSX__) || ...
    > > ...
    > >     gettimeofday(...);
    > > ...
    > > #endif

    >
    > And you say that using a lib will create portability issues?
    > What happens when you encounter a new OS?  (And of course,
    > conditional compilation can quickly make the code completely
    > unreadable.)
    >
    > > my personal suggestion is to create a function, or maybe
    > > collection of them, which provide a consistent interface to
    > > OS-specific behaviors, and keep any OS specific parts confined
    > > to these functions.


    yep


    > In other words, write a library that someone else has already
    > written.
    >
    > Sometimes it's necessary---there can be a number of reasons not
    > to use an existing library.  But you shouldn't rewrite it unless
    > it is necessary for some reason.


    wrapper it. For instance we have a socket interface library that hides
    the differences between Windows and Unix (originally HP-Unix) sockets.
    Personnally I'd like to rewrite it so there was more shared code and
    less ifdefs but it does do the job.
    Nick Keighley, Nov 5, 2009
    #10
  11. Julek

    James Kanze Guest

    Re: Portable library to measure time

    On Nov 5, 10:18 am, Nick Keighley <>
    wrote:
    > On 2 Nov, 10:18, James Kanze <> wrote:


    [...]
    > > Reinventing something that is already available should only
    > > be done when there is a very good reason for not using what
    > > is available. (Copyright restrictions come to mind---some
    > > projects can't use GPL, for example.)


    > as someone who is lumbered with some unsupported 3PLs there
    > can be other reasons. Some 3PLs cost money. Sometimes a lot of
    > money.


    And some are of such low quality that you can't allow them. Or
    you're unsure of future support, or portability (from
    experience, a lot of so-called portable libraries don't work
    with Sun CC).

    [...]
    > > In other words, write a library that someone else has already
    > > written.


    > > Sometimes it's necessary---there can be a number of reasons
    > > not to use an existing library. But you shouldn't rewrite
    > > it unless it is necessary for some reason.


    > wrapper it.


    If it's an essential part of your application, always. Even if
    the library in question is the standard library. Wrappered, and
    you have the chance of replacing it, if e.g. it causes
    performance problems.

    --
    James Kanze
    James Kanze, Nov 5, 2009
    #11
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Eli Bendersky
    Replies:
    1
    Views:
    1,153
    Mike Treseler
    Mar 1, 2006
  2. Peng Yu
    Replies:
    7
    Views:
    368
    Anoop Aryal
    Mar 29, 2005
  3. Girish Sahani

    How to measure execution time of a program

    Girish Sahani, Jun 28, 2006, in forum: Python
    Replies:
    0
    Views:
    349
    Girish Sahani
    Jun 28, 2006
  4. Replies:
    7
    Views:
    906
  5. Julek
    Replies:
    11
    Views:
    626
    James Kanze
    Nov 5, 2009
Loading...

Share This Page