[PATCH v2 1/4] system_data_types.7: Add '__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 | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/man7/system_data_types.7 b/man7/system_data_types.7
index e545aa1a0..5f9aa648f 100644
--- a/man7/system_data_types.7
+++ b/man7/system_data_types.7
@@ -40,6 +40,8 @@ system_data_types \- overview of system data types
 .\"		* Description (no "Description" header)
 .\"			A few lines describing the type.
 .\"
+.\"		* Versions (optional)
+.\"
 .\"		* Conforming to (see NOTES)
 .\"			Format: CXY and later; POSIX.1-XXXX and later.
 .\"
@@ -48,6 +50,44 @@ system_data_types \- overview of system data types
 .\"		* Bugs (if any)
 .\"
 .\"		* See also
+.\"------------------------------------- __int128 ---------------------/
+.TP
+.I __int128
+.RS
+.RI [ signed ]
+.I __int128
+.PP
+A signed 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 __int128
+in implementations where
+.I long long
+is less than 128 bits wide.
+.PP
+See also the
+.IR intmax_t ,
+.IR int N _t
+and
+.I unsigned __int128
+types in this page.
+.RE
 .\"------------------------------------- aiocb ------------------------/
 .TP
 .I aiocb
-- 
2.28.0