Newbie gcc question

Newbie gcc question

[Wayne Willson]

I'm a sys/network admin trying to learn C (this could be the root of the
problem) with the GNU C compiler.

In a learning C book I just bought it gives this example

--------------------------------------------
#include <stdio.h>

viod main()
{
        printf("Hello Universe");
}



I type "gcc -o hello hello.c"

This is what I get "hello.c: In function `main':
hello.c:6: warning: return type of `main' is not `int'"
------------------------------------------------------

When I try this it works:
#include <stdio.h>

int main()
{
        printf("Hello Universe");
}

------------------------------------------------

This works as well

#include <stdio.h>

main()
{
        printf("Hello Universe");
}

-------------------------------------

Could someone tell me why gcc doesn't work with 'void'  but works with 'int'
and '   ' ?

Thanks

Re: Newbie gcc question

[Tim Prince]

>why gcc doesn't work with 'void'  but works with 'int'
>and '   ' ?

There must be something in the comp.lang.c FAQ on this; this is one of the
great gulfs between the Microsoft camp and the rest of the C world.  Most
environments where C programs run expect main() to return an int status code,
and getting this wrong is just as bad as it would be inside your program.  C++
gets even more wrought up about this; C has some historical loopholes where
failure to declare is made to default to int, of which this is one.  Speaking
as a Fortran programmer who has to work in environments which expect programs
to run like C, and has a great familiarity with undeclared things.
Tim Prince
tprince@computer.org

Re: Newbie gcc question

[Chris Gregory]

On Sun, 12 Sep 1999 17:30:24 -0500, Wayne Willson <wmw_will@yahoo.com> wrote:

>I'm a sys/network admin trying to learn C (this could be the root of the
>problem) with the GNU C compiler.
>
>In a learning C book I just bought it gives this example
>
>--------------------------------------------
>#include <stdio.h>
>
>viod main()
>{
>        printf("Hello Universe");
>}
>
>
>
>I type "gcc -o hello hello.c"
>
>This is what I get "hello.c: In function `main':
>hello.c:6: warning: return type of `main' is not `int'"
>------------------------------------------------------

Well, it still worked, you got a warning not an error.  Even when I don't need
a return I usually just accept that main is supposed to return an int and just
add a return 0; to the end of the program.  It shuts up the annoying warning.

-- 

Chris Gregory <cmg5@home.com>

Newbie gcc question

[Wayne Willson]

I'm a sys/network admin trying to learn C (this could be the root of the
problem) with the GNU C compiler.

In a learning C book I just bought it gives this example

--------------------------------------------
#include <stdio.h>

viod main()
{
        printf("Hello Universe");
}



I type "gcc -o hello hello.c"

This is what I get "hello.c: In function `main':
hello.c:6: warning: return type of `main' is not `int'"
------------------------------------------------------

When I try this it works:
#include <stdio.h>

int main()
{
        printf("Hello Universe");
}

------------------------------------------------

This works as well

#include <stdio.h>

main()
{
        printf("Hello Universe");
}

-------------------------------------

Could someone tell me why gcc doesn't work with 'void'  but works with 'int'
and '   ' ?

Thanks

Re: Newbie gcc question

[Tim Prince]

>why gcc doesn't work with 'void'  but works with 'int'
>and '   ' ?

There must be something in the comp.lang.c FAQ on this; this is one of the
great gulfs between the Microsoft camp and the rest of the C world.  Most
environments where C programs run expect main() to return an int status code,
and getting this wrong is just as bad as it would be inside your program.  C++
gets even more wrought up about this; C has some historical loopholes where
failure to declare is made to default to int, of which this is one.  Speaking
as a Fortran programmer who has to work in environments which expect programs
to run like C, and has a great familiarity with undeclared things.
Tim Prince
tprince@computer.org

Re: Newbie gcc question

[Chris Gregory]

On Sun, 12 Sep 1999 17:30:24 -0500, Wayne Willson <wmw_will@yahoo.com> wrote:

>I'm a sys/network admin trying to learn C (this could be the root of the
>problem) with the GNU C compiler.
>
>In a learning C book I just bought it gives this example
>
>--------------------------------------------
>#include <stdio.h>
>
>viod main()
>{
>        printf("Hello Universe");
>}
>
>
>
>I type "gcc -o hello hello.c"
>
>This is what I get "hello.c: In function `main':
>hello.c:6: warning: return type of `main' is not `int'"
>------------------------------------------------------

Well, it still worked, you got a warning not an error.  Even when I don't need
a return I usually just accept that main is supposed to return an int and just
add a return 0; to the end of the program.  It shuts up the annoying warning.

-- 

Chris Gregory <cmg5@home.com>

Re: Newbie gcc question

[Tim Prince]

>why gcc doesn't work with 'void'  but works with 'int'
>and '   ' ?

There must be something in the comp.lang.c FAQ on this; this is one of the
great gulfs between the Microsoft camp and the rest of the C world.  Most
environments where C programs run expect main() to return an int status code,
and getting this wrong is just as bad as it would be inside your program.  C++
gets even more wrought up about this; C has some historical loopholes where
failure to declare is made to default to int, of which this is one.  Speaking
as a Fortran programmer who has to work in environments which expect programs
to run like C, and has a great familiarity with undeclared things.
Tim Prince
tprince@computer.org

Re: Newbie gcc question

[Chris Gregory]

On Sun, 12 Sep 1999 17:30:24 -0500, Wayne Willson <wmw_will@yahoo.com> wrote:

>I'm a sys/network admin trying to learn C (this could be the root of the
>problem) with the GNU C compiler.
>
>In a learning C book I just bought it gives this example
>
>--------------------------------------------
>#include <stdio.h>
>
>viod main()
>{
>        printf("Hello Universe");
>}
>
>
>
>I type "gcc -o hello hello.c"
>
>This is what I get "hello.c: In function `main':
>hello.c:6: warning: return type of `main' is not `int'"
>------------------------------------------------------

Well, it still worked, you got a warning not an error.  Even when I don't need
a return I usually just accept that main is supposed to return an int and just
add a return 0; to the end of the program.  It shuts up the annoying warning.

-- 

Chris Gregory <cmg5@home.com>

Newbie gcc question

[Wayne Willson]

I'm a sys/network admin trying to learn C (this could be the root of the
problem) with the GNU C compiler.

In a learning C book I just bought it gives this example

--------------------------------------------
#include <stdio.h>

viod main()
{
        printf("Hello Universe");
}



I type "gcc -o hello hello.c"

This is what I get "hello.c: In function `main':
hello.c:6: warning: return type of `main' is not `int'"
------------------------------------------------------

When I try this it works:
#include <stdio.h>

int main()
{
        printf("Hello Universe");
}

------------------------------------------------

This works as well

#include <stdio.h>

main()
{
        printf("Hello Universe");
}

-------------------------------------

Could someone tell me why gcc doesn't work with 'void'  but works with 'int'
and '   ' ?

Thanks

Re: newbie gcc question...

[Michael Kahle]

Claudio,

Thanks for your help!  I just finished downloading the pdf book "Advanced
Linux Programming".  I am going to read some tonight.  Thank you very
much.

Michael

---- "Claudio Bley" <bley@cs.uni-magdeburg.de> wrote:
> >>>>> "Michael" == Michael Kahle <geopoliticus@onebox.com> writes:
> 
>     Michael> I am trying to teach myself the c language and a program
>     Michael> I am creating at compile time is giving me the error:
> 
>     Michael> undefined reference to 'bla_bla1' undefined reference
> to
>     Michael> 'bla_bla2' undefined reference to 'bla_bla3' etc...
> 
>     Michael> This is the first c program I have written that requires
>     Michael> me to use the #include directive in my program.  I have
> a
>     Michael> file called bla_bla.h in this file i have the lines: void
>     Michael> bla_bla1(int); int bla_bla2(int); int bla_bla3(int); I
>     Michael> also have another file called tbla_bla.c that has the
>     Michael> directive: #include "bla_bla.h" in it.  
> 
> Producing an executable program is usually a 2 step process. At first
> you let the compiler generate object files, afterwards the linker
> takes these files and links them together to one executable program.
> 
> So, to generate object files run
> 
> gcc -c <file.c>
> 
> on every C source file you've got.
> 
> Then, run for example:
> 
> gcc foo.o bar.o -lm 
> 
> This will produce the file a.out (use -o <outfile> to name it
> differently) by linking the 2 object files foo.o and bar.o together
> and also linking with the math library when necessary (-lm means to
> search for libm.so or libm.a).
> 
> You should have a look at "Advanced Linux Programming". It gets really
> 'advanced' on some subjects, but it starts out with the basics:
> 
> http://www.advancedlinuxprogramming.com/
> 
> HTH
> Claudio
>  

Re: newbie gcc question...

[Michael Kahle]

Andrea,

Thank you so much for the wonderful example and more importantly the
explanation!  This silly (now I think so!) problem has been plaguing
me for the past 3 days... don't worry, I took many breaks!

I better understand now what is going on and was able to compile and
run my program!

> In you example, you declared bla_bla1(), bla_bla2(), bla_bla3(), etc...
> but 
> you did not define them.

oops! in my program I actually did have the definition in the header
file, I didn't make that clear in my example to the list.

Thanks again.  This was such a huge help to me...

Happy programming!

Michael 

Re: newbie gcc question...

[Andrea 'Fyre Wyzard' Bocci]

Hi Michael

When you include a file using the #include directive, you don't need to 
include it again from the command line.
The you are getting are generated at link time, when gcc tries to determine 
where all the (external) functions and variables you referenced in your 
code are.

A very fast description of what's goin'on:

In C (and C++ and many other languages) you have to make a distinction 
between the DECLARATION of and function (or a variable) and its DEFINITION.

The declaration of a function tells the compiler that, somewhere, there is 
a function with that name, parameters and type. You need only specify the 
types, the names of the arguments are optional.
The definition tells what the function actually does. You must put there 
the names for the parameters, as you will be using them in the function.
Sometimes declaration and definition are referred to as, respectively, 
interface and implementation, because the former tells how a function is 
invoked (how your code will interface with it), and the latter actually 
implements the function.

Example:
void bla_bla1(int);
is a declaration. It tells that there is a function called bla_bla1(), 
taking an int as an argument and returning no value (void).

void bla_bla1(int x) {
   printf ("Blah blah blah... %d\n", x);
}
is a definition. It implements bla_bla1() as a function that prints Blah 
blah blah...* to the standard output.

To use a function in your code, it must have been previously declared. (the 
definition itself counts as a declaration, too.)
That's why, for example, to use the library function printf(), you must 
#include <stdio.h>, the header files that contains the declaration of printf().
When you make a program, all the functions you use must (also that being 
declared) be defined in exactly 1 place, where all the declarations will be 
"pointed at".

Compiling a program is actually made of 2 steps (even if a compiler can 
mask this, doing all the work on a single invocation).
[actually, more that two, but you can look at it in this way as a starting 
point]
During the 1st step, the compiler proper translates all the source files 
(.c, for example) into the respective binary files (.o, or .obj).
During the 2ns step, the linker is invoked, and it merges all the .o files 
and all the specified libraries into a single executable, taking care to 
resolve all the external object; i.e. all the function that are declared 
but not defined are "addressed" to the place where that function is 
defined. This place can be a standard library, linked in automatically (for 
functions like printf() or malloc()), an other library (for example, math 
functions declared in <math.h> are defined in the libm library, linked in 
with the "-lm" option), or in another (.o) file.
If you declare and use a function, but never define it (because you have 
not written the implementation, or not included the .o file or the 
library), you will get undefined references to those functions.

In you example, you declared bla_bla1(), bla_bla2(), bla_bla3(), etc... but 
you did not define them.
A correct example would be in the form of:

/* bla_bla.h */

void bla_bla1(int);
int bla_bla2(int);

/* end of bla_bla.h */


/* bla_bla.c */
#include "bla_bla.h"

void bla_bla1 (int x) {
   printf ("Blah blah blah... %d\n", x);
}

int bla_bla2 (int y) {
   int z = y*y;
   printf ("Blah blah blah... %d\n", z);
   return z;
}

/* end of bla_bla.c */

/* main.c */
#include "bla_bla.h"

int main (int argc, char** argv) {
   bla_bla1 (12);
   bla_bla2 (5);

   return 0;
}

/* end of bla_bla.c */

You can compile and link this all in one step with
gcc main.c bla_bla.c -o bla
which will build an executable name bla ("-o" is used to choose the name of 
the output) , which should print
Blah blah blah... 12
Blah blah blah... 25

If, on the other hand, you want to compile it in two steps, you could do:
gcc main.c -o main.o -c
gcc bla_bla.c -o bla_bla.o -c
The "-c" option instruct the compiler to just compile the code, without 
linking.
Then
gcc main.o bla_bla.o -o bla
will build the same executable as before :-)

I hope to have been clear enough. If you need more answers, feel free to 
write me.

Re: newbie gcc question...

[Claudio Bley]

>>>>> "Michael" == Michael Kahle <geopoliticus@onebox.com> writes:

    Michael> I am trying to teach myself the c language and a program
    Michael> I am creating at compile time is giving me the error:

    Michael> undefined reference to 'bla_bla1' undefined reference to
    Michael> 'bla_bla2' undefined reference to 'bla_bla3' etc...

    Michael> This is the first c program I have written that requires
    Michael> me to use the #include directive in my program.  I have a
    Michael> file called bla_bla.h in this file i have the lines: void
    Michael> bla_bla1(int); int bla_bla2(int); int bla_bla3(int); I
    Michael> also have another file called tbla_bla.c that has the
    Michael> directive: #include "bla_bla.h" in it.  

Producing an executable program is usually a 2 step process. At first
you let the compiler generate object files, afterwards the linker
takes these files and links them together to one executable program.

So, to generate object files run

gcc -c <file.c>

on every C source file you've got.

Then, run for example:

gcc foo.o bar.o -lm 

This will produce the file a.out (use -o <outfile> to name it
differently) by linking the 2 object files foo.o and bar.o together
and also linking with the math library when necessary (-lm means to
search for libm.so or libm.a).

You should have a look at "Advanced Linux Programming". It gets really
'advanced' on some subjects, but it starts out with the basics:

http://www.advancedlinuxprogramming.com/

HTH
Claudio

newbie gcc question...

[Michael Kahle]

hello.  I hope this question is not creating any unnecessary noise. 
If it is, i apologize up front and ask you lead me to the correct faq
or other helpful document.

I am trying to teach myself the c language and a program I am creating
at compile time is giving me the error:

undefined reference to 'bla_bla1'
undefined reference to 'bla_bla2'
undefined reference to 'bla_bla3'
etc...

This is the first c program I have written that requires me to use the
#include directive in my program.
I have a file called
bla_bla.h
in this file i have the lines:
void bla_bla1(int);
int bla_bla2(int);
int bla_bla3(int);
I also have another file called
tbla_bla.c
that has the directive:
#include "bla_bla.h"
in it.  When I try and compile this I get the error above. The files
are all located in the same directory and I run gcc from that directory
with the following command line...
gcc -d -l bla_bla.h bla_bla.c -o bla_bla.o

What is causing this error?!  I know I am doing something wrong.  Unfortunatly
the O'Reilly book I am using for my learning (Practical C Programming)
doesn't give a hint as to what command line options I should be using
when using gcc to include header files.  I have poked around on the net
for my answer and tried quite a few different things.

Please help.  I am new to all of this so please be nice. :)

Thank you very much.

Michael 

Re: newbie gcc question

[Matthew Majka]

Maggie Owens wrote:
> 
> I have a little experience writing C++ in the dos and windows
> environment. Now I am trying to write a c program and compile it in gcc
> on a unix system. As a test, I wrote the traditional hello, world
> program:
>   #include <stdio.h>
>   void main()
>   {
>     printf("Hello, world!");
>   }
> 
> I compiled it using:
>   gcc helloworld.c

gcc helloworld.c -o helloworld
./helloworld

That should do it.  However, ./a,out should have done it also.

Re: newbie gcc question

[Konstantinos Adamopoulos]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 3879 bytes --]

I don't know what kind of system you are using (unix, linux or what),
but anyway here are some suggestions to try:
1. I have never tried Z shell myself. Maybe you should switch to
a different shell by using one of the following commands and then try to
execute your program again:
    csh       
-- to run c shell
    bash       --
to run bash shell
    ksh       
-- to run korn shell
2. If the current directory is not in your path you should always
use ./filename to execute your binary files, for example
    ./a.out
3. Check if the output file (a.out) is executable. Use the command
    ls -l
and you should have a line like the following one for your a.out
file
-rwx------   1 kadamopo 1UGCS4     
6776 Oct 14 06:13 a.out
The important bit is the x (4th characters), which means that your
file is executable. If is not there give the command:
chmod 700 a.out
in order to make your file executable
4. Maybe your compiler is confused with the extension of your file
name, for example .c mean c program, and usually .C or .cpp means c++ program.
In a c program usually you can't use expressions like
void main()
because this is specific for c++ programs and the c compiler is
expecting a returned value. It is better to use something like
  #include <stdio.h>
int main()
{
    printf("Hello, world!");
        return 0;
}
or to rename your file to something like helloworld.cpp or helloworld.C
and try it with its original contents without to change anything.
------------------------------------------------------------------------------------------------------
To conclud:
Your program seems to work fine in my system (running Sun OS and gcc-2.95)
as it is
  #include <stdio.h>
  void main()
  {
    printf("Hello, world!");
  }
when I save it as helloworld.cpp and compile with
gcc helloworld.cpp (then run ./a.out)
or
gcc helloworld.cpp -o helloworld (then run ./helloworld)
When I save it as helloworld.c needs the modification I mentioned before,
and looks like this:
#include <stdio.h>
int main()
{
    printf("Hello, world!");
        return 0;
}
compile with
gcc helloworld.c (then run ./a.out)
or
gcc helloworld.c -o helloworld (then run ./helloworld)
------------------------------------------------------------------------------------------------------
Hope that's a bit of help,
Kostas
 
Maggie Owens wrote:
I have a little experience writing C++ in the dos
and windows
environment. Now I am trying to write a c program and compile it in
gcc
on a unix system. As a test, I wrote the traditional hello, world
program:
  #include <stdio.h>
  void main()
  {
    printf("Hello, world!");
  }
I compiled it using:
  gcc helloworld.c
Now, I have a.out, which appears to be executable.
I am using the z shell.
I tried typing:
   a.out
and got:
   zsh: command not found: a.out
so I tried
   sh a.out
and got
   a.out: (M-^A)^C^A^K: not found
   a.out: syntax error at line 10: `;;' unexpected
finally, I tried
   ./a.out
and got nothing in response
I feel abysmally stupid. How can I execute my program?
Thanks in advance
--
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--
====================================================
Konstantinos Adamopoulos
Final Year Student in Computer Science
Department of Computing - University of Bradford
----------------------------------------------------
Phone: +44 1274 238732
Fax  : +1 909 257 7791
email: kadamopo@comp.brad.ac.uk
WWW  : http://www.student.comp.brad.ac.uk/~kadamopo
====================================================
 

Re: newbie gcc question

[Johan Nilson]

On Wed, 13 Oct 1999 17:05:41 -0600, Matthew Majka <mmajka@cs5.dasd.honeywell.com> wrote:

>Maggie Owens wrote:
>> 
>> I have a little experience writing C++ in the dos and windows
>> environment. Now I am trying to write a c program and compile it in gcc
>> on a unix system. As a test, I wrote the traditional hello, world
>> program:
>>   #include <stdio.h>
>>   void main()
>>   {
>>     printf("Hello, world!");
>>   }
>> 
>> I compiled it using:
>>   gcc helloworld.c
>
>gcc helloworld.c -o helloworld
>./helloworld
>
>That should do it.  However, ./a,out should have done it also.

or simply renaming a.out to a.exe, and then running it

/Johan

newbie gcc question

[Maggie Owens]

I have a little experience writing C++ in the dos and windows
environment. Now I am trying to write a c program and compile it in gcc
on a unix system. As a test, I wrote the traditional hello, world
program:
  #include <stdio.h>
  void main()
  {
    printf("Hello, world!");
  }

I compiled it using:
  gcc helloworld.c
Now, I have a.out, which appears to be executable.

I am using the z shell.
I tried typing:
   a.out
and got:
   zsh: command not found: a.out
so I tried
   sh a.out
and got
   a.out: (M-^A)^C^A^K: not found
   a.out: syntax error at line 10: `;;' unexpected
finally, I tried
   ./a.out
and got nothing in response

I feel abysmally stupid. How can I execute my program?
Thanks in advance


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Re: newbie gcc question

[Maggie Owens]

Thank you all for your kind help and detailed instructions!

The solution to the problem was simple, and I suppose it might have
something to do with my terminal type:
I had to add a \n to the end of the printf statement, so it now reads:
  printf("Hello, world!\n");
Now it works as expected when I type
  ./a.out

Cool.


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Re: newbie gcc question

[Matthew Majka]

Johan Nilson wrote:
> 
> On Wed, 13 Oct 1999 17:05:41 -0600, Matthew Majka <mmajka@cs5.dasd.honeywell.com> wrote:
> 
> >Maggie Owens wrote:
> >>
> >> I have a little experience writing C++ in the dos and windows
> >> environment. Now I am trying to write a c program and compile it in gcc
> >> on a unix system. As a test, I wrote the traditional hello, world
> >> program:
> >>   #include <stdio.h>
> >>   void main()
> >>   {
> >>     printf("Hello, world!");
> >>   }
> >>
> >> I compiled it using:
> >>   gcc helloworld.c
> >
> >gcc helloworld.c -o helloworld
> >./helloworld
> >
> >That should do it.  However, ./a,out should have done it also.
> 
> or simply renaming a.out to a.exe, and then running it

He's on UNIX, not Windoze.

Re: newbie gcc question

[Maggie Owens]

Thank you all for your kind help and detailed instructions!

The solution to the problem was simple, and I suppose it might have
something to do with my terminal type:
I had to add a \n to the end of the printf statement, so it now reads:
  printf("Hello, world!\n");
Now it works as expected when I type
  ./a.out

Cool.


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Before you buy.

Re: newbie gcc question

[Matthew Majka]

Johan Nilson wrote:
> 
> On Wed, 13 Oct 1999 17:05:41 -0600, Matthew Majka <mmajka@cs5.dasd.honeywell.com> wrote:
> 
> >Maggie Owens wrote:
> >>
> >> I have a little experience writing C++ in the dos and windows
> >> environment. Now I am trying to write a c program and compile it in gcc
> >> on a unix system. As a test, I wrote the traditional hello, world
> >> program:
> >>   #include <stdio.h>
> >>   void main()
> >>   {
> >>     printf("Hello, world!");
> >>   }
> >>
> >> I compiled it using:
> >>   gcc helloworld.c
> >
> >gcc helloworld.c -o helloworld
> >./helloworld
> >
> >That should do it.  However, ./a,out should have done it also.
> 
> or simply renaming a.out to a.exe, and then running it

He's on UNIX, not Windoze.

Re: newbie gcc question

[Johan Nilson]

On Wed, 13 Oct 1999 17:05:41 -0600, Matthew Majka <mmajka@cs5.dasd.honeywell.com> wrote:

>Maggie Owens wrote:
>> 
>> I have a little experience writing C++ in the dos and windows
>> environment. Now I am trying to write a c program and compile it in gcc
>> on a unix system. As a test, I wrote the traditional hello, world
>> program:
>>   #include <stdio.h>
>>   void main()
>>   {
>>     printf("Hello, world!");
>>   }
>> 
>> I compiled it using:
>>   gcc helloworld.c
>
>gcc helloworld.c -o helloworld
>./helloworld
>
>That should do it.  However, ./a,out should have done it also.

or simply renaming a.out to a.exe, and then running it

/Johan

Re: newbie gcc question

[Konstantinos Adamopoulos]

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I don't know what kind of system you are using (unix, linux or what),
but anyway here are some suggestions to try:
1. I have never tried Z shell myself. Maybe you should switch to
a different shell by using one of the following commands and then try to
execute your program again:
    csh       
-- to run c shell
    bash       --
to run bash shell
    ksh       
-- to run korn shell
2. If the current directory is not in your path you should always
use ./filename to execute your binary files, for example
    ./a.out
3. Check if the output file (a.out) is executable. Use the command
    ls -l
and you should have a line like the following one for your a.out
file
-rwx------   1 kadamopo 1UGCS4     
6776 Oct 14 06:13 a.out
The important bit is the x (4th characters), which means that your
file is executable. If is not there give the command:
chmod 700 a.out
in order to make your file executable
4. Maybe your compiler is confused with the extension of your file
name, for example .c mean c program, and usually .C or .cpp means c++ program.
In a c program usually you can't use expressions like
void main()
because this is specific for c++ programs and the c compiler is
expecting a returned value. It is better to use something like
  #include <stdio.h>
int main()
{
    printf("Hello, world!");
        return 0;
}
or to rename your file to something like helloworld.cpp or helloworld.C
and try it with its original contents without to change anything.
------------------------------------------------------------------------------------------------------
To conclud:
Your program seems to work fine in my system (running Sun OS and gcc-2.95)
as it is
  #include <stdio.h>
  void main()
  {
    printf("Hello, world!");
  }
when I save it as helloworld.cpp and compile with
gcc helloworld.cpp (then run ./a.out)
or
gcc helloworld.cpp -o helloworld (then run ./helloworld)
When I save it as helloworld.c needs the modification I mentioned before,
and looks like this:
#include <stdio.h>
int main()
{
    printf("Hello, world!");
        return 0;
}
compile with
gcc helloworld.c (then run ./a.out)
or
gcc helloworld.c -o helloworld (then run ./helloworld)
------------------------------------------------------------------------------------------------------
Hope that's a bit of help,
Kostas
 
Maggie Owens wrote:
I have a little experience writing C++ in the dos
and windows
environment. Now I am trying to write a c program and compile it in
gcc
on a unix system. As a test, I wrote the traditional hello, world
program:
  #include <stdio.h>
  void main()
  {
    printf("Hello, world!");
  }
I compiled it using:
  gcc helloworld.c
Now, I have a.out, which appears to be executable.
I am using the z shell.
I tried typing:
   a.out
and got:
   zsh: command not found: a.out
so I tried
   sh a.out
and got
   a.out: (M-^A)^C^A^K: not found
   a.out: syntax error at line 10: `;;' unexpected
finally, I tried
   ./a.out
and got nothing in response
I feel abysmally stupid. How can I execute my program?
Thanks in advance
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--
====================================================
Konstantinos Adamopoulos
Final Year Student in Computer Science
Department of Computing - University of Bradford
----------------------------------------------------
Phone: +44 1274 238732
Fax  : +1 909 257 7791
email: kadamopo@comp.brad.ac.uk
WWW  : http://www.student.comp.brad.ac.uk/~kadamopo
====================================================
 

Re: newbie gcc question

[Matthew Majka]

Maggie Owens wrote:
> 
> I have a little experience writing C++ in the dos and windows
> environment. Now I am trying to write a c program and compile it in gcc
> on a unix system. As a test, I wrote the traditional hello, world
> program:
>   #include <stdio.h>
>   void main()
>   {
>     printf("Hello, world!");
>   }
> 
> I compiled it using:
>   gcc helloworld.c

gcc helloworld.c -o helloworld
./helloworld

That should do it.  However, ./a,out should have done it also.

newbie gcc question

[Maggie Owens]

I have a little experience writing C++ in the dos and windows
environment. Now I am trying to write a c program and compile it in gcc
on a unix system. As a test, I wrote the traditional hello, world
program:
  #include <stdio.h>
  void main()
  {
    printf("Hello, world!");
  }

I compiled it using:
  gcc helloworld.c
Now, I have a.out, which appears to be executable.

I am using the z shell.
I tried typing:
   a.out
and got:
   zsh: command not found: a.out
so I tried
   sh a.out
and got
   a.out: (M-^A)^C^A^K: not found
   a.out: syntax error at line 10: `;;' unexpected
finally, I tried
   ./a.out
and got nothing in response

I feel abysmally stupid. How can I execute my program?
Thanks in advance


--
Autoreplies will (hopefully) bounce. To reply to me, please send mail
to mmowens at panix dot com.


Sent via Deja.com http://www.deja.com/
Before you buy.