Pragma to disable warning number 4505 in Microsoft C8
#pragma warning(disable:4505)

Error Number	Error Message
C4019	empty statement at global scope
C4100	unreferenced formal parameter
C4101	unreferenced local variable
C4701	local variable "identifier" may be used without having been initialized. This warning is given only when compiling with the C8 /Oe global register allocation command-line option.
C4702	unreachable code. This warning is given only when compiling with one of the C8 global optimization options (/Oe, /Og or /Ol)
C4705	statement has no effect
C4706	assignment within conditional expression
C4723	potential divide by 0

Table 2-1: Some interesting Microsoft C8 warning messages.

CompilerAssert() define
#define CompilerAssert(exp) extern char _CompilerAssert[(exp)?1:-1]

Sample CompilerAssert() usage
...
char buffer[BUFFER_SIZE];
...
CompilerAssert(ISPOWER2(sizeof(buffer)));
...

Testing CompilerAssert(), file test.c
#define CompilerAssert(exp) extern char _CompilerAssert[(exp)?1:-1]

int main(void)
{
    /*--- A forced CompilerAssert ---*/
    long lVal;
    CompilerAssert(sizeof(lVal)==0);
    return 0;

} /* main */
 


Compiling test.c under Microsoft C8, should produce an error C2118
cl test.c
test.c(7) : error C2118: negative subscript
 


Compiling test.c under UNIX cc, should produce an error message
cc test.c
test.c: In function `main':
test.c:7: size of array `_CompilerAssert' is negative

Sample variable declaration one
char (*buffer)[80];
  ^   ^  ^     ^
  4   2  1     3

Sample variable declaration two
int (*(*testing)(int))[10];
 ^   ^ ^   ^      ^    ^
 6   4 2   1      3    5

Sample variable declaration three: signal function
void (*signal(int, void (*)(int)))(int);
 ^    ^  ^     ^    ^    ^   ^      ^
 8    6  1     2    5    3   4      7

PSTR is a variable that is a character pointer
char *PSTR;

PSTR is a new type that is a character pointer
typedef char *PSTR;

Code that works, but is a bad programming practice
typedef int x;
int main(void)
{
    x x;
    return 0;

} /* main */

CSCHAR define
#define BASEDIN(seg) _based(_segname(#seg))
#define CSCHAR static char BASEDIN(_CODE)

CSCHAR is a great way of placing read-only strings in the code segment.

Using CSCHAR
CSCHAR szFile[]=__FILE__;
...
OutputName(szFile);

Sample code
#include <stdio.h>
int main(void)
{
    printf( "String: %s" "One","Two" "Three" );
    return 0;

} /* main */


Output from the sample code
String: TwoThreeOne

Splitting up long strings
#include <stdio.h>
int main(void)
{
    printf( "This is an example of using C's ability to\n"
            "contatenate adjacent string literals.  It\n"
            "is a great way to get ONE printf to display\n"
            "a help message.\n" );
    return 0;

} /* main */

Placing macro arguments in a string literal
#define PRINTD(var) printf( "Variable " #var "=%d\n", var )

PRINTD() example
#include <stdio.h>
#define PRINTD(var) printf( "Variable " #var "=%d\n", var )
int main(void)
{
    int nTest=10;
    PRINTD(nTest);
    return 0;

} /* main */


PRINTD() example output
Variable nTest=10

Printf() prototype for Microsoft C8 in stdio.h
int __cdecl printf(const char *, ...);

Printf example
printf( "Testing %s %d", pString, nNum );

Figure 2-1: Pushing function arguments left to right.

Figure 2-2: Pushing function arguments right to left.

Code sample showing dangling else problem
if (test1)
    if (test2) {
        ...
        }
else {
    ...
    }

Code sample rewritten to eliminate dangling else problem
if (test1) {
    if (test2) {
        ...
        }
    }
else {
    ...
    }

strncpy() problem, but code may still work
#include <stdio.h>
#include <string.h>

int main(void)
{
    char buffer[11];
    strncpy( buffer, "hello there", sizeof(buffer) );
    printf( "%s", buffer );
    return 0;

} /* main */

Short-circuit logic example
if ((lpMem) && (*lpMem=='A')) {
    (code body)
    }

De Morgans laws
1.  !(a && b) == (!a || !b)
2.  !(a || b) == (!a && !b)

SQUARE() macro, has problems
#define SQUARE(x) x*x

SQUARE() macro, has problems
#define SQUARE(x) (x)*(x)

SQUARE() macro, final form
#define SQUARE(x) ((x)*(x))

A macro that needs a scope, has problems
#define POW3(x,y) int i; for(i=0; i<y; ++i) {x*=3;}

A macro with scope, has problems
#define POW3(x,y) {int i; for(i=0; i<y; ++i) {x*=3;}}

Using POW3(), has problems
if (expression)
    POW3(lNum, nPow);
else
    (statement)

A macro with scope, final form
#define POW3(x,y) do {int i; for(i=0; i<y; ++i) {x*=3;}} while(0)

Pragma to disable warning number 4127 in Microsoft C8
#pragma warning(disable:4127)

Macro containing if/else, has problems
#define ODS(s) if (bDebugging) OutputDebugString(#s)

Macro containing if/else, problem solved
#define ODS(s) if (!bDebugging) {} else OutputDebugString(#s)

WinAssert() syntax
/*--- Ended with a semicolon ---*/
WinAssert(expression);
/*--- Or ended with a block of code ---*/
WinAssert(expression) {
    (block of code)
    }

WinAssert() macro
#define WinAssert(exp) if (!(exp)) {AssertError;} else

The LOOP(), LLOOP() and ENDLOOP macros
#define LOOP(nArg) { int _nMax=nArg; int loop; \
    for (loop=0; loop<_nMax; ++loop)
#define LLOOP(lArg) { long _lMax=lArg; long lLoop; \
    for (lLoop=0; lLoop<_lMax; ++lLoop)
#define ENDLOOP }

Sample code that uses LOOP(), LLOOP() and ENDLOOP
LOOP(10) {
    printf( "%d\n", loop );
    } ENDLOOP
LLOOP(10) {
    printf( "%ld\n", lLoop );
    } ENDLOOP

C++ loop code, with variable declaration problems
for (int loop=0; loop<10; ++loop) {
    ...
    }
...
for (int loop=0; loop<10; ++loop) {
    ...
    }

NUMSTATICELS() desired behavior example
#include <stdio.h>
#define NUMSTATICELS(pArray) (determine pArray array size)
int main(void)
{
    long alNums[100];
    printf( "array size=%d\n", NUMSTATICELS(alNums) );
    return 0;

} /* main */


Desired output
array size=100

NUMSTATICELS() macro
#define NUMSTATICELS(pArray) (sizeof(pArray)/sizeof(*pArray))

Stringizing operator example
#define STRING(x) #x

Token pasting operator example
CSCHAR szPE7008[]="function ptr";
CSCHAR szPE700A[]="string ptr";
CSCHAR szPE7060[]="coords";
...
#define EV(n) {0x##n,szPE##n}
static struct {
    WORD wError;
    LPSTR lpError;
    } BASEDCS ErrorToTextMap[]={ EV(7008), EV(700A), EV(7060) };

Optimize On/Off macros, which do not work
#define OPTIMIZEOFF #pragma optimize("",off)
#define OPTIMIZEON #pragma optimize("",on)

Testing extra preprocessor pass in Microsoft C8 for C code
cl -P test.c
cl -Tctest.i


Testing extra preprocessor pass in Microsoft C8 for C++ code
cl -P test.cpp
cl -Tptest.i

Macro that determines if a number is a power of two
#define ISPOWER2(x) (!((x)&((x)-1)))

Swapping integers x, y without a third integer using C
1.  x ^= y;
2.  y ^= x;
3.  x ^= y;

Two's complement negation as a macro
#define NEGATE(x) (((x)^~0)+1)

Base eight number line
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 ...

Base eight number line as signed numbers
0 1 2 3 -4 -3 -2 -1 0 1 2 3 -4 -3 -2 -1 ...

MakeProcInstance() prototype
FARPROC MakeProcInstance( FARPROC lpProc, HINSTANCE hInst );

Trapping action messages is easier than subclassing is some cases.

Changing a window's client area to behave like the caption area
  case WM_NCHITTEST: {
      LRESULT lRet=DefWindowProc(hWnd, message, wParam, lParam);
      return ((lRet==HTCLIENT)?HTCAPTION:lRet);
      break;
      }