Gammon Forum

$ cat foo.c
#include <stdio.h>

int main(int argc, char** argv)
{
    int i;
    printf("%d", i);
    return 0;
}

$ gcc foo.c -o foo
$ ./foo
0
$ gcc -O2 foo.c -o foo
$ ./foo
2139865432
$   

$ cat test.c
#include <stdio.h>

int main()
{
    int i;
    printf("%d", i);
    return 0;
}


$ gcc test.c -Wall -o test
$ ./test
1073830176 $

    size = sizeof(sock);
    if ( check_bad_desc( new_desc ) )
    {
      set_alarm( 0 );
      return;
    }
    set_alarm( 20 );
    alarm_section = "new_descriptor::accept";
    if ( ( desc = accept( new_desc, (struct sockaddr *) &sock, &size) ) < 0 )
    {
	perror( "New_descriptor: accept" );
	sprintf(bugbuf, "[*****] BUG: New_descriptor: accept");
	log_string_plus( bugbuf, LOG_COMM, sysdata.log_level );
	set_alarm( 0 );
	return;
    }
    if ( check_bad_desc( new_desc ) )
    {
      set_alarm( 0 );
      return;
    }

  if (getsockname(d->descriptor, (struct sockaddr *)&us, &ulen) < 0)
  {
    perror("set_auth: getsockname");
    ENDRET("Set_auth: getsockname error for %s@%s.", "(getsockname error)");
  }
  if (getpeername(d->descriptor, (struct sockaddr *)&them, &tlen) < 0)
  {
    perror("set_auth: getpeername");
    ENDRET("Set_auth: getpeername error for %s@%s.", "(getpeername error)");
  }

static int bit_tonumber (lua_State *L)
  {

  Integer result = 0;
  unsigned int base = luaL_optint(L, 2, 10);

  // get text to convert
  const unsigned char * text = luaL_checkstring (L, 1);
  const unsigned char * p;
  unsigned char c;
  unsigned int digit;
  Integer maxvalue;
  int negative = 0;

kc@persephone:~/Desktop$ gcc --version
gcc (GCC) 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

kc@persephone:~/Desktop$ cat test.c
#include <stdio.h>

int main() {
    int i;
    printf("%d\n", i);
    return 0;
}

kc@persephone:~/Desktop$ gcc test.c -Wall -o test
kc@persephone:~/Desktop$ ./test
-1209006080
kc@persephone:~/Desktop$ ./test
-1208350720
kc@persephone:~/Desktop$ ./test
-1209026560
kc@persephone:~/Desktop$ gcc -O2 test.c -Wall -o test
test.c: In function 'main':
test.c:5: warning: 'i' is used uninitialised in this function
kc@persephone:~/Desktop$ ./test
1
kc@persephone:~/Desktop$ ./test
1
kc@persephone:~/Desktop$ ./test
1
kc@persephone:~/Desktop$ 

lua_bits.c: In function ‘bit_tonumber’:
lua_bits.c:79: warning: pointer targets in assignment differ in signedness
lua_bits.c:108: error: invalid operands to binary -

static int bit_tonumber (lua_State *L)
  {

  Integer result = 0;
  unsigned int base = luaL_optint(L, 2, 10);

  // get text to convert
  const char * text = luaL_checkstring (L, 1);
  const unsigned char * p;
  unsigned char c;
  unsigned int digit;
  Integer maxvalue;
  int negative = 0;

  if (base != 10)
    luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");

  // maximum value before multiply by the base
  maxvalue = 4503599627370496 / base;   // 2^52

  // skip whitespace
  for (p = text; isspace (*p); p++)
    ;  // skip leading spaces

  // look for sign
  if (*p == '-')
    {
    negative = 1;
    p++;
    }
  else if (*p == '+')
    p++;


  while ((c = *p++))
    {

    // The largest mantissa a double can have it 52 bits
    if (result >= maxvalue)
      luaL_error (L, "Number too big");

    if (isdigit (c))
      digit = c - '0';
    else if (isalpha (c))
      digit = toupper (c) - 'A' + 10;
    else
      digit = 999;   // bad digit - force error in next line

    if (digit >= base)
      luaL_error (L, "Bad digit ('%c') at position %i",
                  c, (int) (p - text));

    result = result * base + digit;
    } // end while

  if (negative)
    result = -result;

  lua_pushnumber (L, result);

  return 1;  // number of result fields
  } // end of bit_tonumber