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authorUlrich Drepper <drepper@redhat.com>2001-04-09 04:55:59 +0000
committerUlrich Drepper <drepper@redhat.com>2001-04-09 04:55:59 +0000
commiteacde9d0818dac743bc5c2562e35f0a6e949327e (patch)
treed117012b09ea03667334e4fb4be8ab15c41509d5 /manual
parent4c4505561671f07c4f1b9e39cc0a0fa271a6c8be (diff)
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Update.
2001-04-08 Hans-Peter Nilsson <hp@axis.com> * sysdeps/unix/sysv/linux/cris/Dist: New file. * sysdeps/unix/sysv/linux/cris/Makefile: New file. * sysdeps/unix/sysv/linux/cris/_G_config.h: New file. * sysdeps/unix/sysv/linux/cris/bits/fcntl.h: New file. * sysdeps/unix/sysv/linux/cris/bits/mman.h: New file. * sysdeps/unix/sysv/linux/cris/bits/resource.h: New file. * sysdeps/unix/sysv/linux/cris/brk.c: New file. * sysdeps/unix/sysv/linux/cris/chown.c: New file. * sysdeps/unix/sysv/linux/cris/clone.S: New file. * sysdeps/unix/sysv/linux/cris/fchown.c: New file. * sysdeps/unix/sysv/linux/cris/fcntl.c: New file. * sysdeps/unix/sysv/linux/cris/fxstat.c: New file. * sysdeps/unix/sysv/linux/cris/getegid.c: New file. * sysdeps/unix/sysv/linux/cris/geteuid.c: New file. * sysdeps/unix/sysv/linux/cris/getgid.c: New file. * sysdeps/unix/sysv/linux/cris/getgroups.c: New file. * sysdeps/unix/sysv/linux/cris/getresgid.c: New file. * sysdeps/unix/sysv/linux/cris/getresuid.c: New file. * sysdeps/unix/sysv/linux/cris/getrlimit.c: New file. * sysdeps/unix/sysv/linux/cris/getrlimit64.c: New file. * sysdeps/unix/sysv/linux/cris/getuid.c: New file. * sysdeps/unix/sysv/linux/cris/lchown.c: New file. * sysdeps/unix/sysv/linux/cris/lockf64.c: New file. * sysdeps/unix/sysv/linux/cris/lxstat.c: New file. * sysdeps/unix/sysv/linux/cris/mmap.S: New file. * sysdeps/unix/sysv/linux/cris/mmap64.S: New file. * sysdeps/unix/sysv/linux/cris/msgctl.c: New file. * sysdeps/unix/sysv/linux/cris/profil-counter.h: New file. * sysdeps/unix/sysv/linux/cris/register-dump.h: New file. * sysdeps/unix/sysv/linux/cris/semctl.c: New file. * sysdeps/unix/sysv/linux/cris/setegid.c: New file. * sysdeps/unix/sysv/linux/cris/seteuid.c: New file. * sysdeps/unix/sysv/linux/cris/setfsgid.c: New file. * sysdeps/unix/sysv/linux/cris/setfsuid.c: New file. * sysdeps/unix/sysv/linux/cris/setgid.c: New file. * sysdeps/unix/sysv/linux/cris/setgroups.c: New file. * sysdeps/unix/sysv/linux/cris/setregid.c: New file. * sysdeps/unix/sysv/linux/cris/setresgid.c: New file. * sysdeps/unix/sysv/linux/cris/setresuid.c: New file. * sysdeps/unix/sysv/linux/cris/setreuid.c: New file. * sysdeps/unix/sysv/linux/cris/setrlimit.c: New file. * sysdeps/unix/sysv/linux/cris/setuid.c: New file. * sysdeps/unix/sysv/linux/cris/shmctl.c: New file. * sysdeps/unix/sysv/linux/cris/socket.S: New file. * sysdeps/unix/sysv/linux/cris/sys/ucontext.h: New file. * sysdeps/unix/sysv/linux/cris/syscall.S: New file. * sysdeps/unix/sysv/linux/cris/sysdep.S: New file. * sysdeps/unix/sysv/linux/cris/sysdep.h: New file. * sysdeps/unix/sysv/linux/cris/vfork.S: New file. * sysdeps/unix/sysv/linux/cris/xstat.c: New file. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * sysdeps/cris/Dist: New file. * sysdeps/cris/Implies: New file. * sysdeps/cris/Makefile: New file. * sysdeps/cris/__longjmp.S: New file. * sysdeps/cris/_mcount.S: New file. * sysdeps/cris/bits/endian.h: New file. * sysdeps/cris/bits/setjmp.h: New file. * sysdeps/cris/bits/string.h: New file. * sysdeps/cris/dl-machine.h: New file. * sysdeps/cris/elf/start.S: New file. * sysdeps/cris/machine-gmon.h: New file. * sysdeps/cris/memcopy.h: New file. * sysdeps/cris/memusage.h: New file. * sysdeps/cris/setjmp.S: New file. * sysdeps/cris/sysdep.h: New file. * sysdeps/cris/wordcopy.c: New file. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * elf/elf.h: Add new relocations for CRIS. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * shlib-versions: Add cases for Linux on CRIS. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * configure.in (ASM_LINE_SEP tests): Handle CRIS assembly, with ';' for comments and '@' for line separator. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * sysdeps/unix/sysv/linux/hppa/sysdep.h (INLINE_SYSCALL): Fix typo; s/==/=/ for assignment. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * malloc/Makefile: Correct comment; mtrace is Perl, not AWK. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * iconv/gconv_simple.c (internal_ucs4_loop_unaligned): Check for empty input before checking full output. 2001-04-08 Hans-Peter Nilsson <hp@axis.com> * iconv/gconv.c (__gconv): Don't derefer parameter cd before checking if == -1L. 2001-04-08 Ulrich Drepper <drepper@redhat.com> * inet/rexec.c (rexec_af): Avoid calling perror with errno being set.
Diffstat (limited to 'manual')
-rw-r--r--manual/examples/swapcontext.c99
-rw-r--r--manual/filesys.texi85
-rw-r--r--manual/install.texi1
-rw-r--r--manual/setjmp.texi239
-rw-r--r--manual/signal.texi12
5 files changed, 427 insertions, 9 deletions
diff --git a/manual/examples/swapcontext.c b/manual/examples/swapcontext.c
new file mode 100644
index 0000000000..f733510f88
--- /dev/null
+++ b/manual/examples/swapcontext.c
@@ -0,0 +1,99 @@
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ucontext.h>
+#include <sys/time.h>
+
+/* Set by the signal handler. */
+static volatile int expired;
+
+/* The contexts. */
+static ucontext_t uc[3];
+
+/* We do only a certain number of switches. */
+static int switches;
+
+
+/* This is the function doing the work. It is just a
+ skeleton, real code has to be filled in. */
+static void
+f (int n)
+{
+ int m = 0;
+ while (1)
+ {
+ /* This is where the work would be done. */
+ if (++m % 100 == 0)
+ {
+ putchar ('.');
+ fflush (stdout);
+ }
+
+ /* Regularly the @var{expire} variable must be checked. */
+ if (expired)
+ {
+ /* We do not want the program to run forever. */
+ if (++switches == 20)
+ return;
+
+ printf ("\nswitching from %d to %d\n", n, 3 - n);
+ expired = 0;
+ /* Switch to the other context, saving the current one. */
+ swapcontext (&uc[n], &uc[3 - n]);
+ }
+ }
+}
+
+/* This is the signal handler which simply set the variable. */
+void
+handler (int signal)
+{
+ expired = 1;
+}
+
+
+int
+main (void)
+{
+ struct sigaction sa;
+ struct itimerval it;
+ char st1[8192];
+ char st2[8192];
+
+ /* Initialize the data structures for the interval timer. */
+ sa.sa_flags = SA_RESTART;
+ sigfillset (&sa.sa_mask);
+ sa.sa_handler = handler;
+ it.it_interval.tv_sec = 0;
+ it.it_interval.tv_usec = 1;
+ it.it_value = it.it_interval;
+
+ /* Install the timer and get the context we can manipulate. */
+ if (sigaction (SIGPROF, &sa, NULL) < 0
+ || setitimer (ITIMER_PROF, &it, NULL) < 0
+ || getcontext (&uc[1]) == -1
+ || getcontext (&uc[2]) == -1)
+ abort ();
+
+ /* Create a context with a separate stack which causes the
+ function @code{f} to be call with the parameter @code{1}.
+ Note that the @code{uc_link} points to the main context
+ which will cause the program to terminate once the function
+ return. */
+ uc[1].uc_link = &uc[0];
+ uc[1].uc_stack.ss_sp = st1;
+ uc[1].uc_stack.ss_size = sizeof st1;
+ makecontext (&uc[1], (void (*) (void)) f, 1, 1);
+
+ /* Similarly, but @code{2} is passed as the parameter to @code{f}. */
+ uc[2].uc_link = &uc[0];
+ uc[2].uc_stack.ss_sp = st2;
+ uc[2].uc_stack.ss_size = sizeof st2;
+ makecontext (&uc[2], (void (*) (void)) f, 1, 2);
+
+ /* Start running. */
+ swapcontext (&uc[0], &uc[1]);
+ putchar ('\n');
+
+ return 0;
+}
diff --git a/manual/filesys.texi b/manual/filesys.texi
index e54f63dfc5..d7ab4e4a7f 100644
--- a/manual/filesys.texi
+++ b/manual/filesys.texi
@@ -1065,7 +1065,23 @@ purpose is to obtain information about the link. @code{link}, the
function that makes a hard link, does too. It makes a hard link to the
symbolic link, which one rarely wants.
-Prototypes for the functions listed in this section are in
+Some systems have for some functions operating on files have a limit on
+how many symbolic links are followed when resolving a path name. The
+limit if it exists is published in the @file{sys/param.h} header file.
+
+@comment sys/param.h
+@comment BSD
+@deftypevr Macro int MAXSYMLINKS
+
+The macro @code{MAXSYMLINKS} specifies how many symlinks some function
+will follow before returning @code{ELOOP}. Not all functions behave the
+same and this value is not the same a that returned for
+@code{_SC_SYMLOOP} by @code{sysconf}. In fact, the @code{sysconf}
+result can indicate that there is no fixed limit although
+@code{MAXSYMLINKS} exists and has a finite value.
+@end deftypevr
+
+Prototypes for most of the functions listed in this section are in
@file{unistd.h}.
@pindex unistd.h
@@ -1153,6 +1169,73 @@ A hardware error occurred while reading or writing data on the disk.
@c @end group
@end deftypefun
+In some situations it is desirable to resolve all the to get the real
+name of a file where no prefix names a symbolic link which is followed
+and no filename in the path is @code{.} or @code{..}. This is for
+instance desirable if files have to be compare in which case different
+names can refer to the same inode.
+
+@comment stdlib.h
+@comment GNU
+@deftypefun {char *} canonicalize_file_name (const char *@var{name})
+
+The @code{canonicalize_file_name} function returns the absolute name of
+the file named by @var{name} which contains no @code{.}, @code{..}
+components nor any repeated path separators (@code{/}) or symlinks. The
+result is passed back as the return value of the function in a block of
+memory allocated with @code{malloc}. If the result is not used anymore
+the memory should be freed with a call to @code{free}.
+
+In any of the path components except the last one is missing the
+function returns a NULL pointer. This is also what is returned if the
+length of the path reaches or exceeds @code{PATH_MAX} characters. In
+any case @code{errno} is set accordingly.
+
+@table @code
+@item ENAMETOOLONG
+The resulting path is too long. This error only occurs on systems which
+have a limit on the file name length.
+
+@item EACCES
+At least one of the path components is not readable.
+
+@item ENOENT
+The input file name is empty.
+
+@item ENOENT
+At least one of the path components does not exist.
+
+@item ELOOP
+More than @code{MAXSYMLINKS} many symlinks have been followed.
+@end table
+
+This function is a GNU extension and is declared in @file{stdlib.h}.
+@end deftypefun
+
+The Unix standard includes a similar function which differs from
+@code{canonicalize_file_name} in that the user has to provide the buffer
+where the result is placed in.
+
+@comment stdlib.h
+@comment XPG
+@deftypefun {char *} realpath (const char *restrict @var{name}, char *restrict @var{resolved})
+
+The @code{realpath} function behaves just like
+@code{canonicalize_file_name} but instead of allocating a buffer for the
+result it is placed in the buffer pointed to by @var{resolved}.
+
+One other difference is that the buffer @var{resolved} will contain the
+part of the path component which does not exist or is not readable if
+the function returns @code{NULL} and @code{errno} is set to
+@code{EACCES} or @code{ENOENT}.
+
+This function is declared in @file{stdlib.h}.
+@end deftypefun
+
+The advantage of using this function is that it is more widely
+available. The drawback is that it reports failures for long path on
+systems which have no limits on the file name length.
+
@node Deleting Files
@section Deleting Files
@cindex deleting a file
diff --git a/manual/install.texi b/manual/install.texi
index 1d6b39498b..fa8b6183e9 100644
--- a/manual/install.texi
+++ b/manual/install.texi
@@ -424,6 +424,7 @@ following patterns:
@smallexample
alpha@var{*}-@var{*}-linux
arm-@var{*}-linux
+cris-@var{*}-linux
hppa-@var{*}-linux
i@var{x}86-@var{*}-gnu
i@var{x}86-@var{*}-linux
diff --git a/manual/setjmp.texi b/manual/setjmp.texi
index 00e78a51e8..65d62da518 100644
--- a/manual/setjmp.texi
+++ b/manual/setjmp.texi
@@ -12,8 +12,9 @@ functions.
@menu
* Intro: Non-Local Intro. When and how to use these facilities.
-* Details: Non-Local Details. Functions for non-local exits.
+* Details: Non-Local Details. Functions for non-local exits.
* Non-Local Exits and Signals:: Portability issues.
+* System V contexts:: Complete context control a la System V.
@end menu
@node Non-Local Intro, Non-Local Details, , Non-Local Exits
@@ -169,7 +170,7 @@ function containing the @code{setjmp} call that have been changed since
the call to @code{setjmp} are indeterminate, unless you have declared
them @code{volatile}.
-@node Non-Local Exits and Signals,, Non-Local Details, Non-Local Exits
+@node Non-Local Exits and Signals, System V contexts, Non-Local Details, Non-Local Exits
@section Non-Local Exits and Signals
In BSD Unix systems, @code{setjmp} and @code{longjmp} also save and
@@ -211,3 +212,237 @@ argument. If the @code{sigsetjmp} call that set this @var{state} used a
nonzero @var{savesigs} flag, @code{siglongjmp} also restores the set of
blocked signals.
@end deftypefun
+
+@node System V contexts,, Non-Local Exits and Signals, Non-Local Exits
+@section Complete Context Control
+
+The Unix standard one more set of function to control the execution path
+and these functions are more powerful than those discussed in this
+chapter so far. These function were part of the original @w{System V}
+API and by this route were added to the Unix API. Beside on branded
+Unix implementations these interfaces are not widely available. Not all
+platforms and/or architectures the GNU C Library is available on provide
+this interface. Use @file{configure} to detect the availability.
+
+Similar to the @code{jmp_buf} and @code{sigjmp_buf} types used for the
+variables to contain the state of the @code{longjmp} functions the
+interfaces of interest here have an appropriate type as well. Objects
+of this type are normally much larger since more information is
+contained. The type is also used in a few more places as we will see.
+The types and functions described in this section are all defined and
+declared respectively in the @file{ucontext.h} header file.
+
+@comment ucontext.h
+@comment SVID
+@deftp {Data Type} ucontext_t
+
+The @code{ucontext_t} type is defined as a structure with as least the
+following elements:
+
+@table @code
+@item ucontext_t *uc_link
+This is a pointer to the next context structure which is used if the
+context described in the current structure returns.
+
+@item sigset_t uc_sigmask
+Set of signals which are blocked when this context is used.
+
+@item stack_t uc_stack
+Stack used for this context. The value need not be (and normally is
+not) the stack pointer. @xref{Signal Stack}.
+
+@item mcontext_t uc_mcontext
+This element contains the actual state of the process. The
+@code{mcontext_t} type is also defined in this header but the definition
+should be treated as opaque. Any use of knowledge of the type makes
+applications less portable.
+
+@end table
+@end deftp
+
+Objects of this type have to be created by the user. The initialization
+and modification happens through one of the following functions:
+
+@comment ucontext.h
+@comment SVID
+@deftypefun int getcontext (ucontext_t *@var{ucp})
+The @code{getcontext} function initializes the variable pointed to by
+@var{ucp} with the context of the calling thread. The context contains
+the content of the registers, the signal mask, and the current stack.
+Executing the contents would start at the point where the
+@code{getcontext} call just returned.
+
+The function returns @code{0} if succesful. Otherwise it returns
+@code{-1} and sets @var{errno} accordingly.
+@end deftypefun
+
+The @code{getcontext} function is similar to @code{setjmp} but it does
+not provide an indication of whether the function returns for the first
+time or whether the initialized context was used and the execution is
+resumed at just that point. If this is necessary the user has to take
+determine this herself. This must be done carefully since the context
+contains registers which might contain register variables. This is a
+good situation to define variables with @code{volatile}.
+
+Once the context variable is initialized it can be used as is or it can
+be modified. The latter is normally done to implement co-routines or
+similar constructs. The @code{makecontext} function is what has to be
+used to do that.
+
+@comment ucontext.h
+@comment SVID
+@deftypefun void makecontext (ucontext_t *@var{ucp}, void (*@var{func}) (void), int @var{argc}, @dots{})
+
+The @var{ucp} parameter passed to the @code{makecontext} shall be
+initialized by a call to @code{getcontext}. The context will be
+modified to in a way so that if the context is resumed it will start by
+calling the function @code{func} which gets @var{argc} integer arguments
+passed. The integer arguments which are to be passed should follow the
+@var{argc} parameter in the call to @code{makecontext}.
+
+Before the call to this function the @code{uc_stack} and @code{uc_link}
+element of the @var{ucp} structure should be initialized. The
+@code{uc_stack} element describes the stack which is used for this
+context. No two contexts which are used at the same time should use the
+same memory region for a stack.
+
+The @code{uc_link} element of the object pointed to by @var{ucp} should
+be a pointer to the context to be executed when the function @var{func}
+returns or it should be a null pointer. See @code{setcontext} for more
+information about the exact use.
+@end deftypefun
+
+While allocating the memory for the stack one has to be careful. Most
+modern processors keep track of whether a certain memory region is
+allowed to contain code which is executed or not. Data segments and
+heap memory is normally not tagged to allow this. The result is that
+programs would fail. Examples for such code include the calling
+sequences the GNU C compiler generates for calls to nested functions.
+Safe ways to allocate stacks correctly include using memory on the
+original threads stack or explicitly allocate memory tagged for
+execution using (@pxref{Memory-mapped I/O}).
+
+@strong{Compatibility note}: The current Unix standard is very imprecise
+about the way the stack is allocated. All implementations seem to agree
+that the @code{uc_stack} element must be used but the values stored in
+the elements of the @code{stack_t} value are unclear. The GNU C library
+and most other Unix implementations require the @code{ss_sp} value of
+the @code{uc_stack} element to point to the base of the memory region
+allocated for the stack and the size of the memory region is stored in
+@code{ss_size}. There are implements out there which require
+@code{ss_sp} to be set to the value the stack pointer will have (which
+can depending on the direction the stack grows be different). This
+difference makes the @code{makecontext} function hard to use and it
+requires detection of the platform at compile time.
+
+@comment ucontext.h
+@comment SVID
+@deftypefun int setcontext (const ucontext_t *@var{ucp})
+
+The @code{setcontext} function restores the context described by
+@var{ucp}. The context is not modified and can be reused as often as
+wanted.
+
+If the context was created by @code{getcontext} execution resumes with
+the registers filled with the same values and the same stack as if the
+@code{getcontext} call just returned.
+
+If the context was modified with a call to @code{makecontext} execution
+continues with the function passed to @code{makecontext} which gets the
+specified parameters passed. If this function returns execution is
+resumed in the context which was referenced by the @code{uc_link}
+element of the context structure passed to @code{makecontext} at the
+time of the call. If @code{uc_link} was a null pointer the application
+terminates in this case.
+
+Since the context contains information about the stack no two threads
+should use the same context at the same time. The result in most cases
+would be disastrous.
+
+The @code{setcontext} function does not return unless an error occurred
+in which case it returns @code{-1}.
+@end deftypefun
+
+The @code{setcontext} function simply replaces the current context with
+the one described by the @var{ucp} parameter. This is often useful but
+there are situations where the current context has to be preserved.
+
+@comment ucontext.h
+@comment SVID
+@deftypefun int swapcontext (ucontext_t *restrict @var{oucp}, const ucontext_t *restrict @var{ucp})
+
+The @code{swapcontext} function is similar to @code{setcontext} but
+instead of just replacing the current context the latter is first saved
+in the object pointed to by @var{oucp} as if this was a call to
+@code{getcontext}. The saved context would resume after the call to
+@code{swapcontext}.
+
+Once the current context is saved the context described in @var{ucp} is
+installed and execution continues as described in this context.
+
+If @code{swapcontext} succeeds the function does not return unless the
+context @var{oucp} is used without prior modification by
+@code{makecontext}. The return value in this case is @code{0}. If the
+function fails it returns @code{-1} and set @var{errno} accordingly.
+@end deftypefun
+
+@heading Example for SVID Context Handling
+
+The easiest way to use the context handling functions is as a
+replacement for @code{setjmp} and @code{longjmp}. The context contains
+on most platforms more information which might lead to less surprises
+but this also means using these functions is more expensive (beside
+being less portable).
+
+@smallexample
+int
+random_search (int n, int (*fp) (int, ucontext_t *))
+@{
+ volatile int cnt = 0;
+ ucontext_t uc;
+
+ /* @r{Safe current context.} */
+ if (getcontext (&uc) < 0)
+ return -1;
+
+ /* @r{If we have not tried @var{n} times try again.} */
+ if (cnt++ < n)
+ /* @r{Call the function with a new random number}
+ @r{and the context}. */
+ if (fp (rand (), &uc) != 0)
+ /* @r{We found what we were looking for.} */
+ return 1;
+
+ /* @r{Not found.} */
+ return 0;
+@}
+@end smallexample
+
+Using contexts in such a way enables emulating exception handling. The
+search functions passed in the @var{fp} parameter could be very large,
+nested, and complex which would make it complicated (or at least would
+require a lot of code) to leave the function with an error value which
+has to be passed down to the caller. By using the context it is
+possible to leave the search function in one step and allow restarting
+the search which also has the nice side effect that it can be
+significantly faster.
+
+Something which is harder to implement with @code{setjmp} and
+@code{longjmp} is to switch temporarily to a different execution path
+and then resume where execution was stopped.
+
+@smallexample
+@include swapcontext.c.texi
+@end smallexample
+
+This an example how the context functions can be used to implement
+co-routines or cooperative multi-threading. All that has to be done is
+to call every once in a while @code{swapcontext} to continue running a
+different context. It is not allowed to do the context switching from
+the signal handler directly since neither @code{setcontext} nor
+@code{swapcontext} are functions which can be called from a signal
+handler. But setting a variable in the signal handler and checking it
+in the body of the functions which are executed. Since
+@code{swapcontext} is saving the current context it is possible to have
+multiple different scheduling points in the code. Execution will always
+resume where it was left.
diff --git a/manual/signal.texi b/manual/signal.texi
index 90839375e2..c92e877113 100644
--- a/manual/signal.texi
+++ b/manual/signal.texi
@@ -1171,7 +1171,7 @@ the signal. These are described in more detail in @ref{Flags for Sigaction}.
@comment signal.h
@comment POSIX.1
-@deftypefun int sigaction (int @var{signum}, const struct sigaction *@var{action}, struct sigaction *@var{old-action})
+@deftypefun int sigaction (int @var{signum}, const struct sigaction *restrict @var{action}, struct sigaction *restrict @var{old-action})
The @var{action} argument is used to set up a new action for the signal
@var{signum}, while the @var{old-action} argument is used to return
information about the action previously associated with this symbol.
@@ -2563,7 +2563,7 @@ The prototype for the @code{sigprocmask} function is in @file{signal.h}.
@comment signal.h
@comment POSIX.1
-@deftypefun int sigprocmask (int @var{how}, const sigset_t *@var{set}, sigset_t *@var{oldset})
+@deftypefun int sigprocmask (int @var{how}, const sigset_t *restrict @var{set}, sigset_t *restrict @var{oldset})
The @code{sigprocmask} function is used to examine or change the calling
process's signal mask. The @var{how} argument determines how the signal
mask is changed, and must be one of the following values:
@@ -3088,8 +3088,8 @@ not require your program to know which direction the stack grows, which
depends on the specific machine and operating system.
@comment signal.h
-@comment BSD
-@deftp {Data Type} {struct sigaltstack}
+@comment XPG
+@deftp {Data Type} stack_t
This structure describes a signal stack. It contains the following members:
@table @code
@@ -3136,8 +3136,8 @@ delivered on the normal user stack.
@end deftp
@comment signal.h
-@comment BSD
-@deftypefun int sigaltstack (const struct sigaltstack *@var{stack}, struct sigaltstack *@var{oldstack})
+@comment XPG
+@deftypefun int sigaltstack (const stack_t *restrict @var{stack}, stack_t *restrict @var{oldstack})
The @code{sigaltstack} function specifies an alternate stack for use
during signal handling. When a signal is received by the process and
its action indicates that the signal stack is used, the system arranges