make UIO_MAXIOV note more prominent

2 files changed, 20 insertions, 5 deletions

diff --git a/lib/libc/sys/read.2 b/lib/libc/sys/read.2
index ae4af1357d8..6d5fc99ad58 100644
--- a/lib/libc/sys/read.2
+++ b/lib/libc/sys/read.2
@@ -56,7 +56,7 @@ of data from the object referenced by the descriptor
 .Fa d
 into the buffer pointed to by
 .Fa buf .
-.Fn Readv
+.Fn \ Readv
 performs the same action, but scatters the input data
 into the 
 .Fa iovcnt
@@ -109,6 +109,13 @@ The system guarantees to read the number of bytes requested if
 the descriptor references a normal file that has that many bytes left
 before the end-of-file, but in no other case.
 .Pp
+Note that
+.Fn readv
+will fail if the value of 
+.Fa iovcnt
+exceedes the constant
+.Fa UIO_MAXIOV .
+.Pp
 .Sh RETURN VALUES
 If successful, the
 number of bytes actually read is returned. Upon reading end-of-file,
@@ -149,7 +156,8 @@ may return one of the following errors:
 .It Bq Er EINVAL
 .Fa Iovcnt
 was less than or equal to 0, or greater than
-.Dv {UIO_MAXIOV} .
+.\".Dv {UIO_MAXIOV} .
+.Fa UIO_MAXIOV
 .It Bq Er EINVAL
 One of the
 .Fa iov_len
diff --git a/lib/libc/sys/write.2 b/lib/libc/sys/write.2
index bb4813789d3..56a32fb542d 100644
--- a/lib/libc/sys/write.2
+++ b/lib/libc/sys/write.2
@@ -55,8 +55,8 @@ attempts to write
 of data to the object referenced by the descriptor
 .Fa d
 from the buffer pointed to by
-.Fa buf .
-.Fn Writev
+.Fa buf . 
+.Fn \ Writev
 performs the same action, but gathers the output data
 from the 
 .Fa iovcnt
@@ -117,6 +117,13 @@ and
 may write fewer bytes than requested;
 the return value must be noted,
 and the remainder of the operation should be retried when possible.
+.Pp                                                                       
+Note that                                                          
+.Fn writev   
+will fail if the value of                                                  
+.Fa iovcnt              
+exceedes the constant
+.Fa UIO_MAXIOV .     
 .Sh RETURN VALUES
 Upon successful completion the number of bytes which were written
 is returned.  Otherwise a -1 is returned and the global variable
@@ -170,7 +177,7 @@ may return one of the following errors:
 .It Bq Er EINVAL
 .Fa Iovcnt
 was less than or equal to 0, or greater than
-.Dv {UIO_MAXIOV} .
+.Fa UIO_MAXIOV .
 .It Bq Er EINVAL
 One of the
 .Fa iov_len