MAXUIDLEN is a numeric constant that specifies the maximum number of characters that some of the Microsoft cryptographic providers will use when obtaining the user ID.MAXUIDLEN is defined in Wincrypt.h.
||When the pszContainer parameter of the CryptAcquireContext function is NULL, some of the Microsoft cryptographic providers use the logon name of the currently logged on user as the key container name. MAXUIDLEN specifies the maximum number of characters, including the terminating NULL character, that these providers will use for the user name.
|Minimum supported client
||Windows XP [desktop apps only]
|Minimum supported server
||Windows Server 2003 [desktop apps only]