: int may be signed or unsigned

Incorrect of course: int is always signed. I was thinking of char.

But may signed int have a different representation than int?

-- Mat.

Hello my name is Jarrod Driscoll, I have a problem. I wrote this program
and compiled it and it works however I keep on getting the following
warning messages. I was wondering if there was anyway around this.
The following warning messages I recieved are
warning return makes integer from pointer without a cast.
warning assignment makes pointer from integer without a cast.

a segment of same code that I have written is a follows :

openfile( char directory[] , char filename[], FILE *filep)
{

        chdir(directory);
        if ( filep = fopen(filename, "r") == NULL )
        {
                printf("Error cant open file \n");
                exit(1);
        }
        else
        printf("File Open \n");

        return(filep);

fgets(line,200,filepointer);
printf("%s\n" , line );

filepointer = (openfile(directory,filename,fp));
readfile(filepointer);

THANKS FOR YOU TIME

JD.

 and (int) vs.

Use int for general integer arguments that can be positive or negative.

On Fri, 22 Aug 1997 14:59:37 +1000, Jarrod Driscoll

Therefore what the compiler is warning you about is true, when
you call the function it returns an int, which you assign to
a pointer (FILE *).

To stop this happening you NEED to give return values to all
your functions.  The above function would become:

  FILE *openfile( char directory[] , char filename[], FILE *filep)
  {

  }

Also if you want a function with no return value, use void, eg

  void functWithNoReturnValue()
  {

  }
<removed code>

From Paul Morris
Software Engineer
GEC Marconi Radar And Defence Systems

These are my thoughts, I think.

  Jarrod,

  If you do not explicitly specify the return value for a function in C, it
will default to the type int.  The function openfile does not have a
return type specified to the compiler presumes that it will be an int.
At the end of openfile the return statement attempts to return a
FILE * into the int value.  Your compiler issues a warning to this effect.

  To remove the warning complete the specification for openfile as

FILE * openfile( char directory[], char filename[], FILE *filep)
{
..

  The second warning would be on the "filepointer = openfile" line in main ().
The warning is issued because the function "int openfile (...)" returns an int
and that value is being saved into filepointer which is declared as a FILE *.

  The second warning will also be removed by the completed declaration
of openfile ().

  Good luck,

  David LaRue
  Team OS/2, ACM, IEEE

JD> Newsgroups: alt.comp.lang.learn.c-c++,comp.lang.c,comp.lang.c++

Is it C or C++?  fopen() and such are features of C; followups set to
comp.lang.c and alt.comp.lang.learn.c-c++.

JD> I keep on getting the following warning messages. I was wondering
JD> if there was anyway around this.  The following warning messages I
JD> recieved are warning return makes integer from pointer without a
JD> cast.  warning assignment makes pointer from integer without a
JD> cast.

JD> openfile( char directory[] , char filename[], FILE *filep)

What type does openfile() return?  You never specify.  I suspect from
the return statement that it should be
FILE *openfile(char directory[], char filename[], FILE *filep)
but unless you explicitly state this the compiler will assume you
meant "int".  The return statement then tries to turn filep into an
int, which is defined but causes a (correct) warning.

JD> {
JD>  
JD>  chdir(directory);
JD>  if ( filep = fopen(filename, "r") == NULL )

If you completely ignore the filep that's passed into the function,
why pass it?  filep's use here could be just as easily done with a
local variable.

JD>  {
JD>          printf("Error cant open file \n");
JD>          exit(1);

In ANSI C, exit() can only return 0, EXIT_SUCCESS, or EXIT_FAIILURE.

JD>  }
JD>  else
JD>  printf("File Open \n");
JD>
JD>  return(filep);
JD> }
JD>
JD> readfile( FILE *filepointer)

What does readfile return?  Anything?  You should explicitly declare
it as a void function if it doesn't.

JD> {
JD> char line[200];
JD>
JD> fgets(line,200,filepointer);
JD> printf("%s\n" , line );
JD> }
JD>
JD>
JD> main ()

Either int main(void) or int main(int argc, char **argv).

JD> {
JD> FILE *filepointer, *fp;
JD> char directory[50], filename[50];
JD>
JD> filepointer = (openfile(directory,filename,fp));

fp's only purpose here is to be passed to openfile(), which
subsequently ignores its (completely random) contents.  It should
probably go away.  It would also be a really good idea to somehow get
something into directory and filename before you call openfile();
right now, they're complete garbage.

JD> readfile(filepointer);

You should, for propriety's sake, fclose(filepointer);

JD> }

--
 _____________________________
/                             \  "...electronic spam is about as appealing
|          David Maze         |   as the luncheon meat of the same name..."

| http://donut.mit.edu/dmaze/ |  -- _The San Jose Mercury News_,
\_____________________________/                              August 8, 1997

FILE *openfile( char directory[] , char filename[], FILE *filep)

otherwise it is wrongly assumed that openfile returns an int (even though
it says return filep; the return type is determined by the prototype, not
by what gets returned). The program may still work, because pointers and
ints can be of the same size on your computer. But on some other computers,
they are not.

Pedantic extras:

- it's int main(void)
- main should return a value, like return 0, before it ends
- you don't need the ( ) around the openfile call.
--

Kurt

--
| Kurt Watzka                             Phone : +49-89-2180-6254

 >   ... I have a problem.
 >   The following warning messages I recieved are
 >   warning return makes integer from pointer without a cast.
 >   warning assignment makes pointer from integer without a cast.

 >   openfile( char directory[] , char filename[], FILE *filep)
 >   {
        [snip...]  
 >           return(filep);
 >   }

You are returning a pointer here, but your function doesn't have
an explicit type.  The default function type is "int".  You should
explicitly declare this function to be a function returning "FILE *".

 >   main ()
 >   {
 >   FILE *filepointer, *fp;
 >   char directory[50], filename[50];
 >  
 >   filepointer = (openfile(directory,filename,fp));

This is your other line generating a warning.  The compiler thinks
openfile returns an integer.  But you are assigning it to a pointer.