svn commit: r228920 - head/share/man/man3

[Ed Schouten]

Author: ed
Date: Tue Dec 27 22:14:35 2011
New Revision: 228920
URL: http://svn.freebsd.org/changeset/base/228920

Log:
  Document restriction on 32-bits and 64-bits datatypes.

Modified:
  head/share/man/man3/ATOMIC_VAR_INIT.3

Modified: head/share/man/man3/ATOMIC_VAR_INIT.3
==============================================================================
--- head/share/man/man3/ATOMIC_VAR_INIT.3	Tue Dec 27 22:13:51 2011	(r228919)
+++ head/share/man/man3/ATOMIC_VAR_INIT.3	Tue Dec 27 22:14:35 2011	(r228920)
@@ -281,6 +281,12 @@ This behaviour cannot be emulated for ol
 To prevent unintended non-atomic access to these variables, this header
 file places the atomic variable in a structure when using an older
 compiler.
+.Pp
+When using GCC on architectures on which it lacks support for built-in
+atomic intrinsics, these macros may emit function calls to fallback
+routines.
+These fallback routines are only implemented for 32-bits and 64-bits
+datatypes, if supported by the CPU.
 .Sh SEE ALSO
 .Xr pthread 3 ,
 .Xr atomic 9