Win32 Windows Volume Program and Code Example 6
Getting the System Information Program Example
Create a new Win32 console application project and give a suitable project name.
Add the source file and give a suitable name.
Add the following source code.
#include <windows.h>
#include <stdio.h>
WCHAR* envVarStrings[] =
{
LOS = %OS%,
LPATH = %PATH%,
LHOMEPATH = %HOMEPATH%,
LTEMP = %TEMP%
};
#define ENV_VAR_STRING_COUNT (sizeof(envVarStrings)/sizeof(WCHAR*))
#define INFO_BUFFER_SIZE 32767
void printError( WCHAR* msg );
int wmain( )
{
DWORD i;
WCHAR infoBuf[INFO_BUFFER_SIZE];
DWORD bufCharCount = INFO_BUFFER_SIZE;
// Get and display the name of the computer.
bufCharCount = INFO_BUFFER_SIZE;
if(!GetComputerName( infoBuf, &bufCharCount))
printError(LGetComputerName());
wprintf(L\nComputer name: %s, infoBuf);
// Get and display the user name.
bufCharCount = INFO_BUFFER_SIZE;
if(!GetUserName(infoBuf, &bufCharCount))
printError(LGetUserName());
wprintf(L\nUser name: %s, infoBuf);
// Get and display the system directory.
if(!GetSystemDirectory(infoBuf, INFO_BUFFER_SIZE))
printError(LGetSystemDirectory());
wprintf(L\nSystem Directory: %s, infoBuf);
// Get and display the Windows directory.
if(!GetWindowsDirectory(infoBuf, INFO_BUFFER_SIZE))
printError(LGetWindowsDirectory());
wprintf(L\nWindows Directory: %s, infoBuf);
// Expand and display a few environment variables.
wprintf(L\n\nSome of Environment Variables:);
for(i = 0; i < ENV_VAR_STRING_COUNT; ++i)
{
bufCharCount = ExpandEnvironmentStrings(envVarStrings[i], infoBuf,INFO_BUFFER_SIZE);
if( bufCharCount > INFO_BUFFER_SIZE )
wprintf(L\n\t(Buffer too small to expand: \%s\),envVarStrings[i]);
else if(!bufCharCount)
printError(LExpandEnvironmentStrings());
else
wprintf(L\n %s, infoBuf);
}
wprintf(L\n);
return 0;
}
void printError(WCHAR* msg)
{
DWORD eNum;
WCHAR sysMsg[256];
WCHAR* p;
eNum = GetLastError();
FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, eNum,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
sysMsg, 256, NULL);
// Trim the end of the line and terminate it with a null
p = sysMsg;
while(( *p > 31) || (*p == 9))
++p;
do
{
*p-- = 0;
} while((p >= sysMsg) && (( *p == '.') || (*p < 33)));
// Display the message
wprintf(L\n\t%s failed with error %d (%s), msg, eNum, sysMsg);
}
Build and run the project. The following screenshot is an output sample.
