获取环境变量

PTSTR pszValue = NULL;
PCTSTR pszVariableName = TEXT("JAVA_HOME");
// Get the size of the buffer that is required to store the value
DWORD dwResult = GetEnvironmentVariable(pszVariableName, pszValue, 0);  
if (dwResult != 0)
{// Allocate the buffer to store the environment variable value
　　DWORD size = dwResult * sizeof(TCHAR);
　　pszValue = (PTSTR)malloc(size);
　　GetEnvironmentVariable(pszVariableName, pszValue, size);
　　_tprintf(TEXT("%s=%s\n"), pszVariableName, pszValue);
　　free(pszValue);
} 
else 
{
　　_tprintf(TEXT("'%s'=<unknown value>\n"), pszVariableName);
}