@@ -91,6 +91,7 @@ use-nscd = @use_nscd@
build-hardcoded-path-in-tests= @hardcoded_path_in_tests@
build-pt-chown = @build_pt_chown@
pthread-in-libc = @pthread_in_libc@
+man-pages-version = @man_pages_version@
# Build tools.
CC = @CC@
@@ -706,6 +706,7 @@ force_install
bindnow
hardcoded_path_in_tests
enable_timezone_tools
+man_pages_version
rtld_early_cflags
extra_nonshared_cflags
sysheaders
@@ -787,6 +788,7 @@ with_headers
with_nonshared_cflags
with_rtld_early_cflags
with_timeoutfactor
+with_man_pages
enable_sanity_checks
enable_shared
enable_profile
@@ -1509,6 +1511,8 @@ Optional Packages:
build early initialization with additional CFLAGS
--with-timeoutfactor=NUM
specify an integer to scale the timeout
+ --with-man-pages=VERSION
+ tie manual to a specific man-pages version
--with-cpu=CPU select code for CPU variant
Some influential environment variables:
@@ -4091,11 +4095,11 @@ if test x$ac_prog_cxx_stdcxx = xno
then :
{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CXX option to enable C++11 features" >&5
printf %s "checking for $CXX option to enable C++11 features... " >&6; }
-if test ${ac_cv_prog_cxx_cxx11+y}
+if test ${ac_cv_prog_cxx_11+y}
then :
printf %s "(cached) " >&6
else $as_nop
- ac_cv_prog_cxx_cxx11=no
+ ac_cv_prog_cxx_11=no
ac_save_CXX=$CXX
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
@@ -4137,11 +4141,11 @@ if test x$ac_prog_cxx_stdcxx = xno
then :
{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CXX option to enable C++98 features" >&5
printf %s "checking for $CXX option to enable C++98 features... " >&6; }
-if test ${ac_cv_prog_cxx_cxx98+y}
+if test ${ac_cv_prog_cxx_98+y}
then :
printf %s "(cached) " >&6
else $as_nop
- ac_cv_prog_cxx_cxx98=no
+ ac_cv_prog_cxx_98=no
ac_save_CXX=$CXX
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
@@ -4374,6 +4378,17 @@ fi
printf "%s\n" "#define TIMEOUTFACTOR $timeoutfactor" >>confdefs.h
+man_pages_version=6.8
+
+
+# Check whether --with-man-pages was given.
+if test ${with_man_pages+y}
+then :
+ withval=$with_man_pages; man_pages_version=$withval
+fi
+
+
+
# Check whether --enable-sanity-checks was given.
if test ${enable_sanity_checks+y}
then :
@@ -168,6 +168,15 @@ AC_ARG_WITH([timeoutfactor],
[timeoutfactor=1])
AC_DEFINE_UNQUOTED(TIMEOUTFACTOR, $timeoutfactor)
+man_pages_version=6.8
+
+AC_ARG_WITH([man-pages],
+ AS_HELP_STRING([--with-man-pages=VERSION],
+ [tie manual to a specific man-pages version]),
+ [man_pages_version=$withval],
+ [])
+AC_SUBST(man_pages_version)
+
AC_ARG_ENABLE([sanity-checks],
AS_HELP_STRING([--disable-sanity-checks],
[really do not use threads (should not be used except in special situations) @<:@default=yes@:>@]),
@@ -117,6 +117,7 @@ $(objpfx)stamp-pkgvers: $(common-objpfx)config.make
echo "@set PKGVERSION_DEFAULT" >> $(objpfx)pkgvers-tmp; \
fi
echo "@set REPORT_BUGS_TO $(REPORT_BUGS_TEXI)" >> $(objpfx)pkgvers-tmp
+ echo "@set man_pages_version $(man-pages-version)" >> $(objpfx)pkgvers-tmp; \
echo "@end ifclear" >> $(objpfx)pkgvers-tmp
$(move-if-change) $(objpfx)pkgvers-tmp $(objpfx)pkgvers.texi
touch $@
@@ -65,6 +65,7 @@ directly.)
* Interrupt Input:: Getting an asynchronous signal when
input arrives.
* IOCTLs:: Generic I/O Control operations.
+* Other Low-Level I/O APIs:: Other low-level-I/O-related functions.
@end menu
@@ -2214,6 +2215,8 @@ file descriptor, or until the timeout period expires.
There is another example showing the use of @code{select} to multiplex
input from multiple sockets in @ref{Server Example}.
+For an alternate interface to this functionality, see @code{poll}
+(@pxref{Other Low-Level I/O APIs}).
@node Synchronizing I/O
@section Synchronizing I/O operations
@@ -4633,5 +4636,24 @@ Most IOCTLs are OS-specific and/or only used in special system utilities,
and are thus beyond the scope of this document. For an example of the use
of an IOCTL, see @ref{Out-of-Band Data}.
-@c FIXME this is undocumented:
-@c dup3
+@node{Other Low-Level I/O APIs}
+@section{Other low-level-I/O-related functions}
+
+@deftp {Data Type} {struct epoll_event}
+@standards{Linux, sys/epoll.h}
+@end deftp
+
+@deftypefun int poll (struct pollfd *@var{fds}, nfds_t @var{nfds}, int @var{timeout})
+
+@xref{System Calls} for information on this and other system calls.
+@end deftypefun
+
+@deftypefun int epoll_create(int @var{size})
+
+@xref{System Calls} for information on this and other system calls.
+@end deftypefun
+
+@deftypefun int epoll_wait(int @var{epfd}, struct epoll_event *@var{events}, int @var{maxevents}, int @var{timeout})
+
+@xref{System Calls} for information on this and other system calls.
+@end deftypefun
@@ -41,6 +41,7 @@ aren't documented either so far.
is to make it work with Inetd.
* Socket Options:: Miscellaneous low-level socket options.
* Networks Database:: Accessing the database of network names.
+* Other Socket APIs:: Other socket-related functions.
@end menu
@node Socket Concepts
@@ -3134,38 +3135,8 @@ You can use plain @code{recv} (@pxref{Receiving Data}) instead of
treat all possible senders alike). Even @code{read} can be used if
you don't want to specify @var{flags} (@pxref{I/O Primitives}).
-@ignore
-@c sendmsg and recvmsg are like readv and writev in that they
-@c use a series of buffers. It's not clear this is worth
-@c supporting or that we support them.
-@c !!! they can do more; it is hairy
-
-@deftp {Data Type} {struct msghdr}
-@standards{BSD, sys/socket.h}
-@end deftp
-
-@deftypefun ssize_t sendmsg (int @var{socket}, const struct msghdr *@var{message}, int @var{flags})
-@standards{BSD, sys/socket.h}
-@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
-
-This function is defined as a cancellation point in multi-threaded
-programs, so one has to be prepared for this and make sure that
-allocated resources (like memory, files descriptors, semaphores or
-whatever) are freed even if the thread is cancel.
-@c @xref{pthread_cleanup_push}, for a method how to do this.
-@end deftypefun
-
-@deftypefun ssize_t recvmsg (int @var{socket}, struct msghdr *@var{message}, int @var{flags})
-@standards{BSD, sys/socket.h}
-@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
-
-This function is defined as a cancellation point in multi-threaded
-programs, so one has to be prepared for this and make sure that
-allocated resources (like memory, files descriptors, semaphores or
-whatever) are freed even if the thread is canceled.
-@c @xref{pthread_cleanup_push}, for a method how to do this.
-@end deftypefun
-@end ignore
+If you need more flexibility and/or control over sending and receiving
+packets, see @code{sendmsg} and @code{recvmsg} (@pxref{Other Related APIs}).
@node Datagram Example
@subsection Datagram Socket Example
@@ -3664,3 +3635,36 @@ returns a null pointer if there are no more entries.
@c libc_lock_unlock @aculock
This function closes the networks database.
@end deftypefun
+
+@node Other Socket APIs
+@section Other Socket APIs
+
+@deftp {Data Type} {struct msghdr}
+@standards{BSD, sys/socket.h}
+@end deftp
+
+@deftypefun ssize_t sendmsg (int @var{socket}, const struct msghdr *@var{message}, int @var{flags})
+@standards{BSD, sys/socket.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+
+@xref{System Calls} for information on this and other system calls.
+
+This function is defined as a cancellation point in multi-threaded
+programs, so one has to be prepared for this and make sure that
+allocated resources (like memory, files descriptors, semaphores or
+whatever) are freed even if the thread is cancel.
+@c @xref{pthread_cleanup_push}, for a method how to do this.
+@end deftypefun
+
+@deftypefun ssize_t recvmsg (int @var{socket}, struct msghdr *@var{message}, int @var{flags})
+@standards{BSD, sys/socket.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+
+@xref{System Calls} for information on this and other system calls.
+
+This function is defined as a cancellation point in multi-threaded
+programs, so one has to be prepared for this and make sure that
+allocated resources (like memory, files descriptors, semaphores or
+whatever) are freed even if the thread is canceled.
+@c @xref{pthread_cleanup_push}, for a method how to do this.
+@end deftypefun
@@ -690,7 +690,34 @@ you don't need to know about it because you can just use @theglibc{}'s
@code{chmod} function.
@cindex kernel call
-System calls are sometimes called kernel calls.
+System calls are sometimes called syscalls or kernel calls, and this
+interface is mostly a purely mechanical translation from the kernel's
+ABI to the C ABI. For the set of syscalls where we do not guarantee
+POSIX Thread cancellation the wrappers only organize the incoming
+arguments from the C calling convention to the calling convention of
+the target kernel. For the set of syscalls where we provided POSIX
+Thread cancellation the wrappers set some internal state in the
+library to support cancellation, but this does not impact the
+behaviour of the syscall provided by the kernel.
+
+@Theglibc{} includes by reference the Linux man-pages
+@value{man_pages_version} documentation to document the listed
+syscalls for the Linux kernel. For reference purposes only the latest
+@uref{https://www.kernel.org/doc/man-pages/,Linux man-pages Project}
+documentation can be accessed from the
+@uref{https://www.kernel.org,Linux kernel} website. Where the syscall
+has more specific documentation in this manual that more specific
+documentation is considered authoritative.
+
+In some cases, if @theglibc{} detects that a system call has been
+superceeded by a more capable one, the wrapper may map the old call to
+the new one. For example, @code{dup2} is implemented via @code{dup3}
+by passing an additional empty flags argument, and @code{open} calls
+@code{openat} passing the additional @code{AT_FDCWD}. Sometimes even
+more is done, such as converting between 32-bit and 64-bit time
+values. In general, though, such processing is only to make the
+system call better match the C ABI, rather than change its
+functionality.
However, there are times when you want to make a system call explicitly,
and for that, @theglibc{} provides the @code{syscall} function.
@@ -712,6 +739,8 @@ we won't describe it here either because anyone who is coding
library source code as a specification of the interface between them
anyway.
+@code{syscall} does not provide cancellation logic, even if the system
+call you're calling is listed as cancellable above.
@code{syscall} is declared in @file{unistd.h}.