1<assertions> 2 <assertion id="1" tag="def:S:42626:42627 pt:CX"> 3The sigwait() function shall select a pending signal from 'set', automatically 4clear it from the system's pending signals, and return that signal number in 5the location represendted by 'sig'. 6 </assertion> 7 <assertion id="2" tag="def:S:42627:42632 pt:CX"> 8If prior to the call to sigwait() there are multiple pending instances of a 9single signal number (and it is implementation-defined that the signal number 10supports queued signals), then the first such queued signal shall cause a 11return from sigwait() and the remainder shall remain queued. 12 </assertion> 13 <assertion id="3" tag="def:S:42627:42632 pt:CX"> 14If prior to the call to sigwait() there are multiple pending instances of a 15single signal number (and it is implementation-defined that the signal number 16DOES NOT support queued signals), then there should be no remaining pending 17signals for that signal number. 18 </assertion> 19 <assertion id="4" tag="def:S:42632:42633 pt:CX"> 20If no signal in 'set' is pending at the time of the call, the thread shall 21be suspended until one or more becomes pending. 22 </assertion> 23 <assertion id="5" tag="def:S:42633:42635 pt:CX"> 24The signals defined by 'set' should have been blocked at the time of the call 25to sigwait(); otherwise the behavior is undefined. The effect of sigwait() on 26the signal actions for the signals in 'set' is unspecified. 27 </assertion> 28 <assertion id="6" tag="def:S:42636:42638 pt:CX"> 29If more than one thread is using sigwait() to wait for the same signal, no more 30than one of these threads shall return from sigwait() with the signal number. 31Which thread returns from sigwait() is unspecified if the signal is generated 32for the process; otherwise only the target thread of the signal can receive the 33signal. 34 </assertion> 35 <assertion id="7" tag="def:S:42639:42641 pt:RTS"> 36Should any of the multiple pending signals in the range SIGRTMIN to SIGRTMAX be 37selected, it shall be the lowest numbered one. The selection order between real 38time and non-realtime signals, or between multiple pending non-realtime signals is unspecified. 39 </assertion> 40 <assertion id="8" tag="def:S:42642:42645 pt:CX"> 41Upon successful completion, sigwait() shall store the signal number of the 42received signal at the location referenced by 'sig' and return zero. 43 </assertion> 44 <assertion id="9" tag="def:S:42642:42645 pt:CX"> 45Upon unsuccess, sigwait() will return with a non-zero error number to indicate 46the error. 47 </assertion> 48 <assertion id="10" tag="def:S:42646:42648 pt:CX"> 49The sigwait() function fails if the 'set' argument contains an invalid 50or unsupported signal number. 51 </assertion> 52</assertions> 53