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$ 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] 

-D name

Predefine name as a macro, with definition 1. 

-D name=definition

The contents of definition are tokenized and processed as if they appeared during translation phase three in a ‘#define’ directive. In particular, the definition will be truncated by embedded newline characters.

If you are invoking the preprocessor from a shell or shell-like program you may need to use the shell's quoting syntax to protect characters such as spaces that have a meaning in the shell syntax.

If you wish to define a function-like macro on the command line, write its argument list with surrounding parentheses before the equals sign (if any). Parentheses are meaningful to most shells, so you will need to quote the option. With sh and csh, -D'name(args...)=definition' works.

-D and -U options are processed in the order they are given on the command line. All -imacros file and -include file options are processed after all -D and -U options. 

-U name

Cancel any previous definition of name, either built in or provided with a -D option. 

-undef

Do not predefine any system-specific or GCC-specific macros. The standard predefined macros remain defined. 

[링크 : https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html]