compilation error

ilnli · 08-05-2007, 11:00 AM

when I try to compile the following code with command

Code:

#include "cdk/cdk.h"

void main()
{
   CDKSCREEN    *cdkscreen;
   CDKLABEL     *demo;
   WINDOW       *screen;
   char         *mesg[4];

   /* Initialize the Cdk screen.        */
   screen = initscr();
   cdkscreen = initCDKScreen (screen);

   /* Set the labels up.                */
   mesg[0] = "<R></B/1>This line should have a yellow foreground and a blue background.<!1>";
   mesg[1] = "</U/2>This line should have a white  foreground and a blue background.<!2>";
   mesg[2] = "<B=+>This is a bullet.";
   mesg[3] = "<I=10>This is indented 10 characters.";
   mesg[4] = "<C>This line should be set to whatever the screen default is.";

   /* Declare the labels.       */
   demo = newCDKLabel (cdkscreen, CENTER, CENTER, mesg, 5, TRUE, TRUE);

   /* Draw the label            */
   drawCDKLabel (demo, TRUE);
   waitCDKLabel (demo, ' ');

   /* Clean up                  */
   destroyCDKLabel (demo);
   destroyCDKScreen (cdkscreen);
   endCDK();
   exit (0);
}

Code:

debian:~/Desktop/cdk-5.0-20060507# gcc    -c test.c -o test.o
test.c: In function ‘main’:
test.c:4: warning: return type of ‘main’ is not ‘int’

but when I try to make the executable it gives me the following error

Code:

debian:~/Desktop/cdk-5.0-20060507# gcc  test.c
test.c: In function ‘main’:
test.c:4: warning: return type of ‘main’ is not ‘int’
/tmp/cc2H5gFa.o: In function `main':
test.c:(.text+0x12): undefined reference to `initscr'
test.c:(.text+0x20): undefined reference to `initCDKScreen'
test.c:(.text+0x80): undefined reference to `newCDKLabel'
test.c:(.text+0xaf): undefined reference to `waitCDKLabel'
test.c:(.text+0xba): undefined reference to `_destroyCDKObject'
test.c:(.text+0xc5): undefined reference to `destroyCDKScreen'
test.c:(.text+0xca): undefined reference to `endCDK'
collect2: ld returned 1 exit status

can anyone please tell what can be the problem?

regards,
Imran

paulsm4 · 08-05-2007, 12:40 PM

Hi -

1. To get rid of this warning, you should:

Quote:

warning: return type of ‘main’ is not ‘int’

Code:

int
main (int argc, char *argv[])

"int main" isn't absolutely necessary (it's just a warning) ... but I would argue it's very good practice. Honest!

2. Fixing this will cause a second warning. You should also change "exit (0)" to:

Code:

  return 0;

Again, it isn't necessary ... but "return 0;" from function "main ()" is simply better form than calling "exit ()".

3. Finally, your program uses CDE ... so you need to include the CDK library when you link your program. For example:

Quote:

gcc -g test.c -o test -lcdk -lncurses

In the above example, "-lcdk" specifies your CDK library. CDK, in turn, will probably need "-lncurses". You don't need "-c" (this example compiles and links in one step), you don't need "-o test.o" ("test.o" is the default object name; re-specifying it is just redundant). The "-g" allows you to run your program in a debugger - always a Good Idea.

'Hope that helps .. PSM

ilnli · 08-05-2007, 07:07 PM

thanks alot it worked