[PATCH 3/4] system_data_types.7: Document ptrdiff_t

[Alejandro Colomar]

Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
---
 man7/system_data_types.7 | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/man7/system_data_types.7 b/man7/system_data_types.7
index 5ef470386..8969ee966 100644
--- a/man7/system_data_types.7
+++ b/man7/system_data_types.7
@@ -62,6 +62,27 @@ system_data_types \- overview of system data types
 .\"
 .\"		* See also
 .TP
+.I ptrdiff_t
+.IP
+Include:
+.I <stddef.h>.
+.IP
+Used for a count of elements, and array indices.
+It is the result of subtracting two pointers.
+According to the C language standard, it shall be a signed integer type
+capable of storing values in the range
+.BR "" [ PTRDIFF_MIN ,
+.BR PTRDIFF_MAX ].
+.IP
+Conforming to: C99 and later; POSIX.1-2001 and later.
+.IP
+See also the
+.\".I regoff_t ,	FIXME: uncomment when regoff_t is documented.
+.I size_t
+and
+.I ssize_t
+types in this page.
+.TP
 .I sigval
 .IP
 Include:
@@ -221,8 +242,10 @@ See also:
 .BR write (2)
 .IP
 See also the
+.I ptrdiff_t
+and
 .I size_t
-type in this page.
+types in this page.
 .TP
 .I suseconds_t
 .IP
-- 
2.28.0