/// <summary>
/// Retrieves the text for the specified console alias and executable.
/// </summary>
/// <param name="Source">The console alias whose text is to be retrieved.</param>
/// <param name="ExeName">The name of the executable file.</param>
/// <returns>On success, the return value is a non-null, non-empty string.
/// If the Source and ExeName do not specify a valid alias, null is returned.</returns>
public static string GetAlias(string Source, string ExeName)
{
// The only reliable way to allocate enough space is to the
// combined length for all aliases.
int length = GetAliasesLength(ExeName);
if (length == 0)
{
// no aliases defined, so just return null
return(null);
}
char[] buff = new char[length];
int rslt = WinCon.GetConsoleAlias(Source, buff, buff.Length, ExeName);
if (rslt == 0)
{
int err = Marshal.GetLastWin32Error();
// GetConsoleAlias fails if it can't find the alias.
// GetLastError returns 31 in that case.
if (err == 31) // ERROR_GEN_FAILURE
{
return(null);
}
throw new IOException("Unable to get alias", err);
}
// Documentation for GetConsoleAlias says that the return value is non-zero
// on success. It appears that the return value is the number of characters
// copied to the buffer (including the 0 terminator), but I can't be
// sure that's reliable.
// go look for the terminator.
int i;
for (i = 0; i < buff.Length; i++)
{
if (buff[i] == '\0')
{
break;
}
}
return(new string(buff, 0, i));
}