.ds rV "function returns the value 0 if successful; otherwise the value -1 is returned and the global variable \\*(vAerrno\fP is set to indicate the error.
.de Rv
.ie \\n(.$==0 \{\
.tm Usage: .Rv [-std] (#\\n(.c)
.\}
.el \{\
. ds mN Rv
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. nr cH \\*(cH
. if (\\n(cH<2):(\\n(cH>3) .tm Usage: .Rv -std sections 2 and 3 only