Wall로 Build 를 하는데 아래와 같은 워닝이 발생해서

구글링좀 하고, 고치기 귀찮아서  MakeFile만 수정해서 올림
연구원 씨가 관심 있으면 고치겠지.....



The following short examples demonstrate my problem:

----Exhibit A
#include <stdio.h>
#include <stdlib.h>

typedef struct {
    int foo;
    int bar;
} item_t;

int return_item (void **item);

int return_item (void **item)
{
    void *mem;

    mem = malloc (1);
    if (mem) {
        *item = mem;
        return 0;
    }
    else
        return 1;
}

int main (int argc, char *argv[])
{
    item_t *item;

    if (return_item ((void **)&item) == 0) {
        printf ("%p\n", item);
        free (item);
    }

    return 0;
}

----Exhibit B
#include <stdio.h>
#include <stdlib.h>

typedef struct {
    int foo;
    int bar;
} item_t;

int return_item (void **item);

int return_item (void **item)
{
    void *mem;

    mem = malloc (1);
    if (mem) {
        *item = mem;
        return 0;
    }
    else
        return 1;
}

int main (int argc, char *argv[])
{
    item_t *item;
    void *item_temp;

    if (return_item (&item_temp) == 0) {
        item = item_temp;
        printf ("%p\n", item);
        free (item);
    }

    return 0;
}
----

The code is a generic example of the problem.  The real code that is
producing the problem is a hashing API which hashes (void *) and hence
uses (void **) as an out parameter type. 

Exhibit A produces a warning as follows:

[nodbug:mato]$ gcc -O2 -Wall -o aliasing-test aliasing-test.c
aliasing-test.c: In function `main':
aliasing-test.c:28: warning: dereferencing type-punned pointer will break strict-aliasing rules

I'm using gcc version 3.3.5 (Debian 1:3.3.5-13) but the problem persists
even when tested with GCC 4.x on newer systems.

Exhibit B is my proposed "fix".  Can anyone advise if the code in
Exhibit A is legitimate, i.e. whether or not it's really violating the
strict aliasing rules as defined by the C standard?  If not, then I
guess the warning is spurious and I can safely use the fix.

If the code is in fact violating the standard then feel free to
enlighten me how to fix it, since it seems like a legitimate thing to do
:-)

Thanks very much for any help,
귀차나서 그대로 긁어 왔습니다.

참고 : http://gcc.gnu.org/ml/gcc-help/2006-08/msg00236.html


음 문제가 되면 삭제 하겠습니다 훗..

워닝 발생

if ( x = getSomethingValue())
{
 ........
}

해결방법
if ( (x = getSomethingValue()) )
{
 ........
}

KIN.....

오늘도 Builder로 써 열심히 Build를 하고 있었다...
나 <--- 난 거의 팀내 잡부로 수 많은 Link Error를 접해보는 사람이다.

아래와 같은 C4430을 마주했다.

Class에서 Member Function을 선언하고, 실제 구현부에서 return 값을 빼먹었을때,
C4430이 여지 없이 일어난다 한번 테스트를 해보길...





MSDN Error 페이지를 살펴 보니 아래와 같은 경우 발생하게 된다.

This error is issued only by the C compiler and occurs only for non-automatic variables. The compiler initializes non-automatic variables at the start of the program and the values they are initialized with must be constant.

Example

The following sample generates C2099.

Copy Code

// C2099.c 
int j; 
int *p; 
j = *p; // C2099 *p is not a constant

C2099 can also occur because the compiler is not able to perform constant folding on an expression under /fp:strict because the floating point precision environment settings (see _controlfp_s for more information) may differ from compile to run time.

When constant folding fails, the compiler invokes dynamic initialization, which is not allowed in C.

To resolve this error, compile the module as a .cpp file or simplify the expression.

For more information, see /fp (Specify Floating-Point Behavior).

The following sample generates C2099.

Copy Code

// C2099_2.c
// compile with: /fp:strict /c
float X = 2.0 - 1.0;   // C2099
float X2 = 1.0;   // OK


Also See  - C/C++ Build Errors

http://msdn.microsoft.com/en-us/library/8x5x43k7(VS.80).aspx