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Groups > comp.lang.c++ > #19029

Re: C/C++ question about dynamic "static struct"

From James Kuyper <jameskuyper@verizon.net>
Newsgroups comp.lang.c++, comp.lang.c
Subject Re: C/C++ question about dynamic "static struct"
Date 2012-10-17 08:29 -0400
Organization A noiseless patient Spider
Message-ID <k5m8bb$fol$1@dont-email.me> (permalink)
References <k5lv0a$orl$1@Kil-nws-1.UCIS.Dal.Ca>

Cross-posted to 2 groups.

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On 10/17/2012 05:49 AM, gus gassmann wrote:
> Hi,
> 
> I have a static struct, defined in a C header file as something like
> 
>   typedef struct
> SomeStruct {	
> 		char *name;
> 		int kind;
> 		int value;
> 	 }

That's not a valid typedef; it's not clear what you intended, but given
the code below, you should probably have moved 'SomeStruct' after the
right curly bracket, and then appended a semicolon.

> and I need to supply (in C++) values to an array of this type. I 
> understand that I can set *static* values by
> 
> static SomeStruct
> myStruct[] = {
> 		{"name1", 1, 17},
> 		{"name2", 7, 25},
> 		{"name3", 3,  6},
> 		{"name4", 0,117}
> 	      };
> 
> However, I need to set dynamic values along these lines (I know that the 
> code does not work):
> 
> static SomeStruct
> myStruct[] = {
> 		{name[0], kind[0], val[0]},
> 		{name[1], kind[1], val[1]},
> 		...	
> 		{name[n], kind[n], val[n]},
> 	      };
> 
> where both the values and the number of values are only known at 
> runtime. I cannot change the definition in the header file; I am not 
> even sure that what I want to do is possible. Any ideas?

It isn't possible to do this in the initializer of a static object. That
initializer is evaluated at the time the object is created, which for
objects with static storage duration, occurs at the start of the
program. If you want the values to be set at run time, you'll have to
use assignment expressions to fill it in, not initialization.

If the array's length is not known until run time, you can't make it a
static array; the best you can do is a static pointer to a dynamically
allocated array, which should be initialized with a null pointer. Make
sure that your code is written in such a way as to guarantee that the
pointer is not dereferenced while null. You could use malloc() to
allocate the array, in either language. However, since the array will be
filled in by C++ code, you'd be better off using a 'new' expression,
which has better type safety.
-- 
James Kuyper

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Thread

C/C++ question about dynamic "static struct" gus gassmann <gus@nospam.com> - 2012-10-17 06:49 -0300
  Re: C/C++ question about dynamic "static struct" Noob <root@127.0.0.1> - 2012-10-17 13:08 +0200
    Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-17 08:19 -0400
    Re: C/C++ question about dynamic "static struct" Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-10-17 15:19 +0000
    Re: C/C++ question about dynamic "static struct" gus gassmann <gus@nospam.com> - 2012-10-17 18:47 -0300
      Re: C/C++ question about dynamic "static struct" Ike Naar <ike@iceland.freeshell.org> - 2012-10-17 22:46 +0000
        Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-18 07:13 +0000
      Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-17 18:58 -0400
        Re: C/C++ question about dynamic "static struct" Stuart <DerTopper@web.de> - 2012-10-18 09:55 +0200
          Re: C/C++ question about dynamic "static struct" jacob navia <jacob@spamsink.net> - 2012-10-18 10:13 +0200
            Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-18 08:23 +0000
              Re: C/C++ question about dynamic "static struct" jacob navia <jacob@spamsink.net> - 2012-10-18 11:17 +0200
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-18 23:37 +1300
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-18 15:35 +0100
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-19 11:40 -0700
            Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-18 21:45 +1300
            Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-18 15:03 +0100
          Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-18 07:18 -0400
            Re: C/C++ question about dynamic "static struct" Stuart <DerTopper@web.de> - 2012-10-18 17:43 +0200
          Re: C/C++ question about dynamic "static struct" William Ahern <william@wilbur.25thandClement.com> - 2012-10-18 13:52 -0700
            Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-19 21:34 +1300
            Re: C/C++ question about dynamic "static struct" Stuart <DerTopper@web.de> - 2012-10-19 11:03 +0200
              Re: C/C++ question about dynamic "static struct" "BartC" <bc@freeuk.com> - 2012-10-20 14:03 +0100
            Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-19 09:27 +0000
              Re: C/C++ question about dynamic "static struct" Stuart <DerTopper@web.de> - 2012-10-19 13:43 +0200
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-19 12:46 +0000
                Re: C/C++ question about dynamic "static struct" ImpalerCore <jadill33@gmail.com> - 2012-10-19 10:14 -0700
                Re: C/C++ question about dynamic "static struct" Paavo Helde <myfirstname@osa.pri.ee> - 2012-10-19 14:53 -0500
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-19 13:52 -0700
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-19 14:13 -0700
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-19 21:24 +0000
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-20 11:47 +1300
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-19 21:22 +0000
              Re: C/C++ question about dynamic "static struct" William Ahern <william@wilbur.25thandClement.com> - 2012-10-19 11:21 -0700
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-19 21:29 +0000
                Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-19 18:53 -0400
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-20 12:13 +1300
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-20 05:55 +0000
                Re: C/C++ question about dynamic "static struct" Stuart <DerTopper@web.de> - 2012-10-20 13:24 +0200
                Re: C/C++ question about dynamic "static struct" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-10-20 12:54 +0100
                Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-20 06:45 -0700
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-21 09:20 +1300
                Re: C/C++ question about dynamic "static struct" Dombo <dombo@disposable.invalid> - 2012-10-20 22:28 +0200
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:05 +0000
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 02:23 -0500
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:32 +0000
                Re: C/C++ question about dynamic "static struct" "BartC" <bc@freeuk.com> - 2012-10-21 11:56 +0100
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 12:54 -0500
                Re: C/C++ question about dynamic "static struct" ptyxs <kerloch@gmail.com> - 2012-10-22 13:43 +0200
                Re: C/C++ question about dynamic "static struct" gwowen <gwowen@gmail.com> - 2012-10-26 03:37 -0700
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-26 07:33 -0500
                Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-27 05:14 -0700
                Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-27 05:08 -0700
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-20 13:44 -0500
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-21 09:09 +1300
                Re: C/C++ question about dynamic "static struct" Dombo <dombo@disposable.invalid> - 2012-10-20 22:31 +0200
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 02:11 -0500
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-21 20:28 +1300
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:40 +0000
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 13:31 -0500
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-22 08:41 +1300
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 16:24 -0500
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-21 15:05 -0700
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-22 07:52 +0000
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-22 14:02 -0500
                Re: C/C++ question about dynamic "static struct" gwowen <gwowen@gmail.com> - 2012-10-26 03:41 -0700
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-26 07:53 -0500
                Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-26 09:51 -0400
                Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-26 13:48 -0400
                Re: C/C++ question about dynamic "static struct" ImpalerCore <jadill33@gmail.com> - 2012-10-26 07:35 -0700
                Re: C/C++ question about dynamic "static struct" Paavo Helde <myfirstname@osa.pri.ee> - 2012-10-26 18:42 -0500
                Re: C/C++ question about dynamic "static struct" ImpalerCore <jadill33@gmail.com> - 2012-10-27 04:21 -0700
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-27 05:04 -0700
                Re: C/C++ question about dynamic "static struct" Paavo Helde <myfirstname@osa.pri.ee> - 2012-10-27 08:06 -0500
                Re: C/C++ question about dynamic "static struct" ImpalerCore <jadill33@gmail.com> - 2012-10-27 06:50 -0700
                Re: C/C++ question about dynamic "static struct" Paavo Helde <myfirstname@osa.pri.ee> - 2012-10-27 11:13 -0500
                Re: C/C++ question about dynamic "static struct" ImpalerCore <jadill33@gmail.com> - 2012-10-27 12:02 -0700
                Re: C/C++ question about dynamic "static struct" Paavo Helde <myfirstname@osa.pri.ee> - 2012-10-27 15:46 -0500
                Re: C/C++ question about dynamic "static struct" ImpalerCore <jadill33@gmail.com> - 2012-10-27 20:24 -0700
                Re: C/C++ question about dynamic "static struct" Dombo <dombo@disposable.invalid> - 2012-10-27 20:11 +0200
                Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-27 05:43 -0700
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-27 13:52 -0500
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-27 14:40 -0500
                Re: C/C++ question about dynamic "static struct" google@ianshome.com - 2012-10-23 12:03 -0700
                Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-27 05:35 -0700
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-27 14:24 -0500
                Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-27 05:36 -0700
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:08 +0000
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 02:51 -0500
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-21 21:09 +1300
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-21 12:16 +0100
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-21 11:55 +0100
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 13:47 -0500
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-22 08:46 +1300
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-22 03:02 +0100
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-22 08:04 +0000
                Re: C/C++ question about dynamic "static struct" Tobias Müller <troplin@bluewin.ch> - 2012-10-21 18:54 +0000
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-22 08:49 +1300
                Re: C/C++ question about dynamic "static struct" Tobias Müller <troplin@bluewin.ch> - 2012-10-21 20:07 +0000
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-21 13:53 -0700
                Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-22 09:54 +1300
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-22 02:41 +0100
                Re: C/C++ question about dynamic "static struct" Tobias Müller <troplin@bluewin.ch> - 2012-10-22 06:12 +0000
                Re: C/C++ question about dynamic "static struct" Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-10-22 20:52 +0000
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-22 16:30 -0700
                Re: C/C++ question about dynamic "static struct" Stuart <DerTopper@web.de> - 2012-10-23 11:22 +0200
                Re: C/C++ question about dynamic "static struct" Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-10-23 16:58 +0000
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-22 02:22 +0100
                Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-27 05:30 -0700
                Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-20 09:06 -0400
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-20 07:43 -0700
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:11 +0000
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-21 11:56 +0100
                Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-21 07:43 -0400
                Re: C/C++ question about dynamic "static struct" Öö Tiib <ootiib@hot.ee> - 2012-10-21 10:36 -0700
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-22 08:13 +0000
                Re: C/C++ question about dynamic "static struct" Steve Thompson <stevet810@gmail.com> - 2012-10-22 15:08 +0000
                Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-22 14:42 -0400
                Re: C/C++ question about dynamic "static struct" Rui Maciel <rui.maciel@gmail.com> - 2012-10-21 10:12 +0100
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-20 13:24 -0500
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:16 +0000
                Re: C/C++ question about dynamic "static struct" Les Cargill <lcargill99@comcast.com> - 2012-10-21 13:57 -0500
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-22 08:17 +0000
              Re: C/C++ question about dynamic "static struct" Fritz Wuehler <fritz@spamexpire-201210.rodent.frell.theremailer.net> - 2012-10-20 22:41 +0200
                Re: C/C++ question about dynamic "static struct" Dombo <dombo@disposable.invalid> - 2012-10-21 01:04 +0200
                Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:23 +0000
            Re: C/C++ question about dynamic "static struct" Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-10-21 19:33 +0000
              Re: C/C++ question about dynamic "static struct" Greg Martin <greg@softsprocket.com> - 2012-10-21 13:20 -0700
                Re: C/C++ question about dynamic "static struct" Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-10-23 15:44 +0000
                Re: C/C++ question about dynamic "static struct" Dombo <dombo@disposable.invalid> - 2012-10-23 20:01 +0200
                Re: C/C++ question about dynamic "static struct" Stuart <DerTopper@web.de> - 2012-10-24 12:01 +0200
                Re: C/C++ question about dynamic "static struct" Dombo <dombo@disposable.invalid> - 2012-10-24 20:31 +0200
          Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-20 06:13 -0700
            Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-21 07:25 +0000
              Re: C/C++ question about dynamic "static struct" Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-10-27 05:54 -0700
          Re: C/C++ question about dynamic "static struct" Old Wolf <oldwolf@inspire.net.nz> - 2012-11-11 14:58 -0800
            Re: C/C++ question about dynamic "static struct" gof@somewhere.invalid (Adam Wysocki) - 2012-11-12 10:33 +0000
      Re: C/C++ question about dynamic "static struct" Ian Collins <ian-news@hotmail.com> - 2012-10-18 12:19 +1300
    Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-18 07:06 +0000
      Re: C/C++ question about dynamic "static struct" Noob <root@127.0.0.1> - 2012-10-18 11:36 +0200
        Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-19 09:28 +0000
          Re: C/C++ question about dynamic "static struct" Noob <root@127.0.0.1> - 2012-10-19 12:07 +0200
            Re: C/C++ question about dynamic "static struct" gus gassmann <gus@nospam.com> - 2012-10-19 08:03 -0300
              Re: C/C++ question about dynamic "static struct" Fritz Wuehler <fritz@spamexpire-201210.rodent.frell.theremailer.net> - 2012-10-20 07:14 +0200
          Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-19 06:58 -0400
  Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-17 08:29 -0400
  Re: C/C++ question about dynamic "static struct" Richard Damon <news.x.richarddamon@xoxy.net> - 2012-10-17 08:35 -0400
    Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-17 08:49 -0400
    Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-18 07:10 +0000
      Re: C/C++ question about dynamic "static struct" Keith Thompson <kst-u@mib.org> - 2012-10-18 12:11 -0700
        Re: C/C++ question about dynamic "static struct" Juha Nieminen <nospam@thanks.invalid> - 2012-10-19 09:30 +0000
          Re: C/C++ question about dynamic "static struct" Keith Thompson <kst-u@mib.org> - 2012-10-19 03:05 -0700
          Re: C/C++ question about dynamic "static struct" James Kuyper <jameskuyper@verizon.net> - 2012-10-19 07:37 -0400

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