구차니의 잡동사니 모음

Private Sub Form1_KeyDown(KeyCode As Integer, Shift As Integer)

    Select Case KeyCode

        Case 37: 'left

        Case 38: ' up

        Case 40: ' down

        Case 39: ' right

        Case 107: ' +

        Case 109: ' -

    End Select

End Sub

Private Sub Form1_KeyUp(KeyCode As Integer, Shift As Integer)

End Sub 

$ gcc -v

Using built-in specs.

COLLECT_GCC=gcc

COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.6/lto-wrapper

Target: x86_64-linux-gnu

Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.6.3-1ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.6 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu

Thread model: posix

gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) 

$ vi void.c

#include <stdio.h>

void main()

{

        void *fp;

        int a = 0;

        fp = &a;

        printf("sizeof(void) %d\n",sizeof(void));

        fp++;

        printf("fp %8X\n",fp);

} 

$ gcc void.c

void.c: In function ‘main’:

void.c:9:2: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘long unsigned int’ [-Wformat]

void.c:10:2: warning: format ‘%X’ expects argument of type ‘unsigned int’, but argument 2 has type ‘void *’ [-Wformat]

void.c:12:2: warning: format ‘%X’ expects argument of type ‘unsigned int’, but argument 2 has type ‘void *’ [-Wformat]

6.23 Arithmetic on void- and Function-Pointers

In GNU C, addition and subtraction operations are supported on pointers to void and on pointers to functions. This is done by treating the size of a void or of a function as 1.

A consequence of this is that sizeof is also allowed on void and on function types, and returns 1.

The option -Wpointer-arith requests a warning if these extensions are used.

[링크 : https://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html]

Compiler Error CS0242

The operation in question is undefined on void pointers

Incrementing a void pointer is not allowed. For more information, see Unsafe Code and Pointers (C# Programming Guide).

[링크 : https://msdn.microsoft.com/en-us/library/dhyat531(v=vs.90).aspx] 

#include <stdio.h>

int printf(const char *format, ...);

int fprintf(FILE *stream, const char *format, ...);

int sprintf(char *str, const char *format, ...);

int snprintf(char *str, size_t size, const char *format, ...);

#include <stdarg.h>

int vprintf(const char *format, va_list ap);

int vfprintf(FILE *stream, const char *format, va_list ap);

int vsprintf(char *str, const char *format, va_list ap);

int vsnprintf(char *str, size_t size, const char *format, va_list ap);

[링크 : http://linux.die.net/man/3/vsprintf]