Hello,

Yes, a libc wrapper would return -1, I've changed the wording and applied other suggestions.

funsafemath (2):
  man/man2/seccomp.2: Document SECCOMP_FILTER_FLAG_TSYNC_ESRCH
  man/man2/seccomp.2: Document SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV

 man/man2/seccomp.2 | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

Range-diff against v1:
1:  c3c3b728b ! 1:  fec59f483 man/man2/seccomp.2: Document SECCOMP_FILTER_FLAG_TSYNC_ESRCH
    @@ Commit message
     
         <https://lore.kernel.org/r/20200304180517.23867-1-tycho@tycho.ws (local)>
     
    +    Signed-off-by: funsafemath [off-list ref]
    +
      ## man/man2/seccomp.2 ##
     @@ man/man2/seccomp.2: .SH DESCRIPTION
      .B SECCOMP_MODE_STRICT
    @@ man/man2/seccomp.2: .SH DESCRIPTION
     +.TP
     +.BR SECCOMP_FILTER_FLAG_TSYNC_ESRCH " (since Linux 5.7)"
     +.\" commit 51891498f2da78ee64dfad88fa53c9e85fb50abf
    -+Return
    ++Fail with
     +.B ESRCH
    -+instead of the thread ID on synchronization failure if
    -+.B  SECCOMP_FILTER_FLAG_TSYNC
    ++instead of returning the thread ID on synchronization failure if
    ++.B SECCOMP_FILTER_FLAG_TSYNC
     +was specified.
     +.IP
     +If this flag is not set, using
2:  423b0141b ! 2:  8ead033b8 man/man2/seccomp.2: Document SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV
    @@ Commit message
     
         Relevant kernel documentation: <Documentation/userspace-api/seccomp_filter.rst>
     
    +    Signed-off-by: funsafemath [off-list ref]
    +
      ## man/man2/seccomp.2 ##
     @@ man/man2/seccomp.2: .SH DESCRIPTION
      .B SECCOMP_FILTER_FLAG_TSYNC
    @@ man/man2/seccomp.2: .SH DESCRIPTION
     +.\" commit c2aa2dfef243efe213a480a1ee8566507a5152f4
     +Ignore non-fatal signals until the supervisor sends a response.
     +.IP
    ++The
     +.B SECCOMP_FILTER_FLAG_NEW_LISTENER
     +flag must be set.
      .RE
-- 
2.52.0