sigreturn.2: refresh the man page

[kib]

Summary

Remove mention of the longjmp(3), which does not use sigreturn.
Try to be more precise when describing the syscall effects.

[emaste]

A couple of grammar edits which I hope are correct and clarify things

lib/libsys/sigreturn.2

58

63

63

It seemed to imply -1 may or may not be returned, but errno will always be set.

I hope this edit suggests that if -1 is returned errno holds the error.

65–68

66–68

[kib]

lib/libsys/sigreturn.2

65–68

Could you please provide the complete sentence? Right now it seems that suggested editing result in

Otherwise, a value of -1 may be returned
.Va errno
set to indicate the error.

which does not read correct to me.

[kib]

Grammar editings

[emaste]

lib/libsys/sigreturn.2

65–68

Ah sorry. I was thinking of something like "a value of -1 may be returned, with errno set to indicate the error."

[kib]

Apply the last suggestion.

[markj]

lib/libsys/sigreturn.2

52

or maybe userspace

58

The sentence structure is clearer without the comma IMO.

59

[kib]

Editing by Mark.

[markj]

lib/libsys/sigreturn.2

52

[kib]

hyphen