getgid.2, getpid.2, getuid.2, pipe.2, syscall.2: Minor tweaks to Eugene's patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/getgid.2

@@ -60,9 +60,9 @@ and
 .BR getegid ()
 wrapper functions transparently deal with the variations across kernel versions.
 .PP
-On Alpha, instead of pair of
+On Alpha, instead of a pair of
 .BR getgid "() and " getegid ()
-system calls, single
+system calls, a single
 .BR getxgid ()
 system call is provided, which returns a pair of real and effective GIDs.
 The glibc
@@ -75,7 +75,7 @@ See
 for details regarding register mapping.
 Other examples of such peculiarity are Alpha-specific
 .BR getxpid "(2) and " getxuid (2),
-along with
+as well as
 .BR pipe (2)
 on several architectures.
 .SH SEE ALSO

man2/getpid.2

@@ -137,9 +137,9 @@ always invoke the actual system call, rather than returning a cached value.
 .\" FIXME .
 .\" Review progress of https://bugzilla.redhat.com/show_bug.cgi?id=1469757
 .PP
-On Alpha, instead of pair of
+On Alpha, instead of a pair of
 .BR getpid "() and " getppid ()
-system calls, single
+system calls, a single
 .BR getxpid ()
 system call is provided, which returns a pair of PID and parent PID.
 The glibc
@@ -152,7 +152,7 @@ See
 for details regarding register mapping.
 Other examples of such peculiarity are Alpha-specific
 .BR getxuid "(2) and " getxgid (2),
-along with
+as well as
 .BR pipe (2)
 on several architectures.
 .SH SEE ALSO

man2/getuid.2

@@ -71,9 +71,9 @@ and
 .BR geteuid ()
 wrapper functions transparently deal with the variations across kernel versions.
 .PP
-On Alpha, instead of pair of
+On Alpha, instead of a pair of
 .BR getuid "() and " geteuid ()
-system calls, single
+system calls, a single
 .BR getxuid ()
 system call is provided, which returns a pair of real and effective UIDs.
 The glibc
@@ -86,7 +86,7 @@ See
 for details regarding register mapping.
 Other examples of such peculiarity are Alpha-specific
 .BR getxpid "(2) and " getxgid (2),
-along with
+as well as
 .BR pipe (2)
 on several architectures.
 .SH SEE ALSO

man2/pipe.2

@@ -194,21 +194,25 @@ version 2.9.
 .SH NOTES
 .\" See http://math-atlas.sourceforge.net/devel/assembly/64.psabi.1.33.ps.Z
 .\" for example, section 3.2.1 "Registers and the Stack Frame".
-SystemV ABI on some architectures allows using more than one register
+The SystemV ABI on some architectures allows the use of more than one register
 for returning multiple values; several architectures
 (namely, Alpha, IA-64, MIPS, SuperH, and SPARC/SPARC64)
-(ab)use this feature in order to implement
+(ab)use this feature in order to implement the
 .BR pipe ()
-system call in a functional manner: it doesn't take any arguments and returns
+system call in a functional manner:
-a pair of file descriptors as a return value on success.
+the call doesn't take any arguments and returns
+a pair of file descriptors as the return value on success.
 The glibc
 .BR pipe ()
-wrapper function transparently deal with this.
+wrapper function transparently deals with this.
 See
 .BR syscall (2)
 for information regarding registers used for storing second file descriptor.
 Other examples of such peculiarity are
-.BR getxpid (2)/ getxuid (2)/ getxgid (2)
+.BR getxpid (2),
+.BR getxuid (2),
+and
+.BR getxgid (2)
 on Alpha.
 .SH CONFORMING TO
 .BR pipe ():

man2/syscall.2

@@ -281,15 +281,19 @@ argument in a single register and not two, as is done in every other ABI.
 .RE
 .IP [6]
 Some architectures
-(namely, Alpha, IA-64, MIPS, SuperH, and SPARC/SPARC64)
+(namely, Alpha, IA-64, MIPS, SuperH, sparc/32, and sparc/64)
-use second return value register in order to pass second return value in
+use an additional register ("Retval2" in the above table)
+to pass back a second return value from the
 .BR pipe (2)
 system call;
-Alpha uses it in the architecture-specific
+Alpha uses this technique in the architecture-specific
-.BR getxpid "(2), " getxuid "(2), and " getxgid (2)
+.BR getxpid (2),
+.BR getxuid (2),
+and
+.BR getxgid (2)
 system calls as well.
 Other architectures do not use the second return value register
-in the system call interface, even if it is defined in the SystemV ABI.
+in the system call interface, even if it is defined in the System V ABI.
 .RE
 .if t \{\
 .in