sigvec(3) - Linux manual page (original) (raw)
sigvec(3) Library Functions Manual sigvec(3)
NAME top
sigvec, sigblock, sigsetmask, siggetmask, sigmask - BSD signal APILIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#include <signal.h>**
**[[deprecated]] int sigvec(int** _sig_**, const struct sigvec ***_vec_**,**
**struct sigvec ***_ovec_**);**
**[[deprecated]] int sigmask(int** _signum_**);**
**[[deprecated]] int sigblock(int** _mask_**);**
**[[deprecated]] int sigsetmask(int** _mask_**);**
**[[deprecated]] int siggetmask(void);**Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
All functions shown above:
Since glibc 2.19:
_DEFAULT_SOURCE
glibc 2.19 and earlier:
_BSD_SOURCEDESCRIPTION top
These functions are provided in glibc as a compatibility interface
for programs that make use of the historical BSD signal API. This
API is obsolete: new applications should use the POSIX signal API
([sigaction(2)](../man2/sigaction.2.html), [sigprocmask(2)](../man2/sigprocmask.2.html), etc.).
The **sigvec**() function sets and/or gets the disposition of the
signal _sig_ (like the POSIX [sigaction(2)](../man2/sigaction.2.html)). If _vec_ is not NULL, it
points to a _sigvec_ structure that defines the new disposition for
_sig_. If _ovec_ is not NULL, it points to a _sigvec_ structure that is
used to return the previous disposition of _sig_. To obtain the
current disposition of _sig_ without changing it, specify NULL for
_vec_, and a non-null pointer for _ovec_.
The dispositions for **SIGKILL** and **SIGSTOP** cannot be changed.
The _sigvec_ structure has the following form:
struct sigvec {
void (*sv_handler)(int); /* Signal disposition */
int sv_mask; /* Signals to be blocked in handler */
int sv_flags; /* Flags */
};
The _svhandler_ field specifies the disposition of the signal, and
is either: the address of a signal handler function; **SIG_DFL**,
meaning the default disposition applies for the signal; or
**SIG_IGN**, meaning that the signal is ignored.
If _svhandler_ specifies the address of a signal handler, then
_svmask_ specifies a mask of signals that are to be blocked while
the handler is executing. In addition, the signal for which the
handler is invoked is also blocked. Attempts to block **SIGKILL** or
**SIGSTOP** are silently ignored.
If _svhandler_ specifies the address of a signal handler, then the
_svflags_ field specifies flags controlling what happens when the
handler is called. This field may contain zero or more of the
following flags:
**SV_INTERRUPT**
If the signal handler interrupts a blocking system call,
then upon return from the handler the system call is not
restarted: instead it fails with the error **EINTR**. If this
flag is not specified, then system calls are restarted by
default.
**SV_RESETHAND**
Reset the disposition of the signal to the default before
calling the signal handler. If this flag is not specified,
then the handler remains established until explicitly
removed by a later call to **sigvec**() or until the process
performs an [execve(2)](../man2/execve.2.html).
**SV_ONSTACK**
Handle the signal on the alternate signal stack
(historically established under BSD using the obsolete
**sigstack**() function; the POSIX replacement is
[sigaltstack(2)](../man2/sigaltstack.2.html)).
The **sigmask**() macro constructs and returns a "signal mask" for
_signum_. For example, we can initialize the _vec.svmask_ field
given to **sigvec**() using code such as the following:
vec.sv_mask = sigmask(SIGQUIT) | sigmask(SIGABRT);
/* Block SIGQUIT and SIGABRT during
handler execution */
The **sigblock**() function adds the signals in _mask_ to the process's
signal mask (like POSIX _sigprocmask(SIGBLOCK)_), and returns the
process's previous signal mask. Attempts to block **SIGKILL** or
**SIGSTOP** are silently ignored.
The **sigsetmask**() function sets the process's signal mask to the
value given in _mask_ (like POSIX _sigprocmask(SIGSETMASK)_), and
returns the process's previous signal mask.
The **siggetmask**() function returns the process's current signal
mask. This call is equivalent to **sigblock**(0).RETURN VALUE top
The **sigvec**() function returns 0 on success; on error, it returns
-1 and sets _[errno](../man3/errno.3.html)_ to indicate the error.
The **sigblock**() and **sigsetmask**() functions return the previous
signal mask.
The **sigmask**() macro returns the signal mask for _signum_.ERRORS top
See the ERRORS under [sigaction(2)](../man2/sigaction.2.html) and [sigprocmask(2)](../man2/sigprocmask.2.html).ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ **Interface** │ **Attribute** │ **Value** │
├──────────────────────────────────────┼───────────────┼─────────┤
│ **sigvec**(), **sigmask**(), **sigblock**(), │ Thread safety │ MT-Safe │
│ **sigsetmask**(), **siggetmask**() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘STANDARDS top
None.HISTORY top
**sigvec**()
**sigblock**()
**sigmask**()
**sigsetmask**()
4.3BSD.
**siggetmask**()
Unclear origin.
**sigvec**()
Removed in glibc 2.21.NOTES top
On 4.3BSD, the **signal**() function provided reliable semantics (as
when calling **sigvec**() with _vec.svmask_ equal to 0). On System V,
**signal**() provides unreliable semantics. POSIX.1 leaves these
aspects of **signal**() unspecified. See [signal(2)](../man2/signal.2.html) for further
details.
In order to wait for a signal, BSD and System V both provided a
function named [sigpause(3)](../man3/sigpause.3.html), but this function has a different
argument on the two systems. See [sigpause(3)](../man3/sigpause.3.html) for details.SEE ALSO top
[kill(2)](../man2/kill.2.html), [pause(2)](../man2/pause.2.html), [sigaction(2)](../man2/sigaction.2.html), [signal(2)](../man2/signal.2.html), [sigprocmask(2)](../man2/sigprocmask.2.html),
[raise(3)](../man3/raise.3.html), [sigpause(3)](../man3/sigpause.3.html), [sigset(3)](../man3/sigset.3.html), [signal(7)](../man7/signal.7.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 sigvec(3)
Pages that refer to this page:sgetmask(2), sigaction(2), signal(2), sigpause(3), sigset(3), signal(7)