diff options
| author | Konstantin Belousov <kib@FreeBSD.org> | 2026-03-08 20:08:42 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2026-03-11 14:38:34 +0000 |
| commit | 9da4a804f0916b24519b8baa7ed460a7ba23d8c8 (patch) | |
| tree | fb6934f299d82f66b9fe28175e8ba093e3e8c16d | |
| parent | e71bfbe2f58ffff8f16a9da075d98fff41671bac (diff) | |
sigreturn.2: refresh the man page
Remove mention of the longjmp(3), which does not use sigreturn.
Try to be more precise when describing the syscall effects.
Reviewed by: emaste, markj
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Differential revision: https://reviews.freebsd.org/D55750
| -rw-r--r-- | lib/libsys/sigreturn.2 | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/lib/libsys/sigreturn.2 b/lib/libsys/sigreturn.2 index 4effeaa5abc7..0e7bca507fc7 100644 --- a/lib/libsys/sigreturn.2 +++ b/lib/libsys/sigreturn.2 @@ -25,7 +25,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd September 6, 2013 +.Dd March 11, 2026 .Dt SIGRETURN 2 .Os .Sh NAME @@ -47,17 +47,25 @@ The thread's signal mask and stack status are restored from the context structure pointed to by .Fa scp . The system call does not return; -the users stack pointer, frame pointer, argument pointer, -and processor status longword are restored from the context. -Execution resumes at the specified pc. -This system call is used by the trampoline code and -.Xr longjmp 3 +the whole userspace context as specified by +.Fa scp , +including the userspace stack pointer, all general-purpose registers, +coprocessor state, process status register, and program counter +are restored from the context. +Execution resumes at the program counter from the specified context. +.Pp +This system call is used by the kernel-provided signal trampoline code, +located in the virtual DSO (VDSO) on some architectures or as raw code +in the shared page if VDSO is not provided, when returning from a signal to the previously executing program. .Sh RETURN VALUES If successful, the system call does not return. -Otherwise, a value of -1 is returned and +Otherwise, a value of -1 may be returned, with .Va errno -is set to indicate the error. +set to indicate the error. +Some conditions detected by hardware result in the delivery of +a synchronous trap signal to the thread, in addition to or instead of +setting the system call error code. .Sh ERRORS The .Fn sigreturn |