[PATCH v2 3/4] system_data_types.7: Add 'unsigned __int128'

[Alejandro Colomar <colomar.6.4.3@gmail.com>]

Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
---
 man7/system_data_types.7 | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/man7/system_data_types.7 b/man7/system_data_types.7
index 5f9aa648f..3cf3f0ec9 100644
--- a/man7/system_data_types.7
+++ b/man7/system_data_types.7
@@ -1822,6 +1822,41 @@ and
 .I void *
 types in this page.
 .RE
+.\"------------------------------------- unsigned __int128 ------------/
+.TP
+.I unsigned __int128
+.RS
+An unsigned integer type
+of a fixed width of exactly 128 bits.
+.PP
+When using GCC,
+it is supported only for targets where
+the compiler is able to generate efficient code for 128-bit arithmetic.
+.PP
+Versions:
+GCC 4.6.0 and later.
+.PP
+Conforming to:
+This is a non-standard extension, present in GCC.
+It is not standardized by the C language standard nor POSIX.
+.PP
+Notes:
+This type is available without including any header.
+.PP
+Bugs:
+It is not possible to express an integer constant of type
+.I unsigned __int128
+in implementations where
+.I unsigned long long
+is less than 128 bits wide.
+.PP
+See also the
+.IR __int128 ,
+.I uintmax_t
+and
+.IR uint N _t
+types in this page.
+.RE
 .\"------------------------------------- va_list ----------------------/
 .TP
 .I va_list
-- 
2.28.0