I tried to post this before and I apologize if I am repeating myself,
but I do not see the post anywhere.
But anyway,
I have a file, data.c, where I define all of my global variables. I
then use the extern keyword to reference those variables from a header
file, data.h, which I include in every file.
I am defining an enum type and variable in data.c:
enum myenum
{
val1,
val2,
val3,
} enum_var;
When I try to reference enum_var in data.h I always get an error. I
have tried numerous ways of referencing it and defining it but I
always seem to get a compiler error.
So how can I externally reference enum_var in data.h so that I can use
enum_var in my program? And if I am totally missing the point on
this, if someone could clear up my confusion about enum or extern that
would be great.
Thank you,
Charlie
10  3034 
On 24 Apr 2007 08:19:40 -0700, in comp.lang.c , Charlie
<ev**********@y ahoo.comwrote:
>I have a file, data.c, where I define all of my global variables. I
then use the extern keyword to reference those variables from a header
file, data.h, which I include in every file.
I am defining an enum type and variable in data.c:
<snip>
>When I try to reference enum_var in data.h I always get an error.
Move the definition of the enum to your header, put the variable in
the source file and the extern reference in the header, below the enum
definition.
By the way, globals are generally considered a bad idea in C.
--
Mark McIntyre
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan
Mark McIntyre wrote:
>
.... snip ...
>
By the way, globals are generally considered a bad idea in C.
Depends on the application.
--
<http://www.cs.auckland .ac.nz/~pgut001/pubs/vista_cost.txt>
<http://www.securityfoc us.com/columnists/423>
<http://www.aaxnet.com/editor/edit043.html>
cbfalconer at maineline.net
--
Posted via a free Usenet account from http://www.teranews.com
CBFalconer wrote:
Mark McIntyre wrote:
>>
... snip ...
>>
By the way, globals are generally considered a bad idea in C.
Depends on the application.
Most natural numbers are greater than 17, despite the existence of
5, 11, and 15.
--
"How am I to understand if you won't teach me?" - Trippa, /Falling/
Hewlett-Packard Limited registered office: Cain Road, Bracknell,
registered no: 690597 England Berks RG12 1HN
In article <f0**********@m urdoch.hpl.hp.c om>,
Chris Dollin <ch**********@h p.comwrote:
>>By the way, globals are generally considered a bad idea in C.
>Depends on the application.
>Most natural numbers are greater than 17, despite the existence of
5, 11, and 15.
In practice, most natural numbers are 1.
-- Richard
--
"Considerat ion shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.
Richard Tobin wrote:
In article <f0**********@m urdoch.hpl.hp.c om>,
Chris Dollin <ch**********@h p.comwrote:
>>>By the way, globals are generally considered a bad idea in C.
>>Depends on the application.
>>Most natural numbers are greater than 17, despite the existence of
5, 11, and 15.
In practice, most natural numbers are 1.
One application global variable does sound about right.
--
"Our future looks secure, but it's all out of our hands." /Man and Machine/
- Magenta
Hewlett-Packard Limited registered no:
registered office: Cain Road, Bracknell, Berks RG12 1HN 690597 England
Chris Dollin said:
Richard Tobin wrote:
>In article <f0**********@m urdoch.hpl.hp.c om>,
Chris Dollin <ch**********@h p.comwrote:
>>>>By the way, globals are generally considered a bad idea in C.
>>>Depends on the application.
>>>Most natural numbers are greater than 17, despite the existence of
5, 11, and 15.
In practice, most natural numbers are 1.
One application global variable does sound about right.
I'd consider 1 to be an upper bound. On average, it should be less than
that.
--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999 http://www.cpax.org.uk
email: rjh at the above domain, - www.
Richard Heathfield wrote:
Chris Dollin said:
>One application global variable does sound about right.
I'd consider 1 to be an upper bound. On average, it should be less than
that.
My last chunk of C [about 20K code+comments] seems to have
8 (according to a makeshift grep of the header files).
Three are equivalents of std[in,out,err], one's a debugging flag,
one's an allocation pool, one's a debugging flag, one's a title
string, and the other two are names/formats of shortcodes.
So seven of them are really constants (ie, they're set up once
and not changed thereafter), of which at least two could be
put behind functional bars.
Not too bad: could do better. (Yes, They could all be wrapped
inside one [pointer to] state variable.)
--
"The path to the web becomes deeper and wider." - October Project
Hewlett-Packard Limited registered office: Cain Road, Bracknell,
registered no: 690597 England Berks RG12 1HN
Chris Dollin wrote:
Three are equivalents of std[in,out,err], one's a debugging flag,
one's an allocation pool, one's a debugging flag, one's a title
string, and the other two are names/formats of shortcodes.
Oops, sorry about the echo echo.
--
"It is seldom good news." ~Crystal Ball~, /The Tough Guide to Fantasyland/
Hewlett-Packard Limited Cain Road, Bracknell, registered no:
registered office: Berks RG12 1HN 690597 England
Richard Tobin wrote:
Chris Dollin <ch**********@h p.comwrote:
>>>By the way, globals are generally considered a bad idea in C.
>>Depends on the application.
>Most natural numbers are greater than 17, despite the existence
of 5, 11, and 15.
In practice, most natural numbers are 1.
Please do not remove attributions for lines you quote.
--
<http://www.cs.auckland .ac.nz/~pgut001/pubs/vista_cost.txt>
<http://www.securityfoc us.com/columnists/423>
<http://www.aaxnet.com/editor/edit043.html>
cbfalconer at maineline.net
--
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create a header file, data.h, where I reference all the variables with
the keyword "extern." I include the header in every file.
I define an enum and variable of that type in data.c,
enum myenum
{
val1,
val2,
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