FindFirstFreeAce function (securitybaseapi.h)

The FindFirstFreeAce function retrieves a pointer to the first free byte in an access control list (ACL).


BOOL FindFirstFreeAce(
  [in]  PACL   pAcl,
  [out] LPVOID *pAce


[in] pAcl

A pointer to an ACL.

[out] pAce

The address of a pointer to the first free position in the ACL created when the function returns. If the ACL is not valid, this parameter is NULL. If the ACL is full, this parameter points to the byte immediately following the ACL.

Return value

If the function succeeds, the function returns nonzero.

If the function fails, it returns zero. To get extended error information, call GetLastError.


Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header securitybaseapi.h (include Windows.h)
Library Advapi32.lib
DLL Advapi32.dll

See also



Low-level Access Control

Low-level Access Control Functions