<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">It was certainly the intent that the memory be allocated. Specifically, if a is the pointer and the region is of length L, then (assuming char *a and ) a[0] … a[L-1] must be valid r and l values at the point of the call.<div class=""><br class=""></div><div class="">Bill</div><div class=""><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;">William Gropp<br class="">Director and Chief Scientist, NCSA<br class="">Thomas M. Siebel Chair in Computer Science<br class="">University of Illinois Urbana-Champaign</div><br class="Apple-interchange-newline"></div></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
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<br class=""><div><blockquote type="cite" class=""><div class="">On Jan 2, 2018, at 1:52 PM, Jeff Hammond <<a href="mailto:jeff.science@gmail.com" class="">jeff.science@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div dir="ltr" class="">If a user passes a (base,size) pair that corresponds to a range of addresses that are not allocated and/or mapped, is that a correct MPI program?<br class=""><br class="">The only text I can find that implies that buffers passed to MPI_Win_create have to be allocated is the following, assuming that one interprets "existing memory" this way. <br class=""><br class="">"Each process specifies a window of existing memory that it exposes to RMA accesses by the processes in the group of comm." (MPI 3.1 11.2.1)<br class=""><br class="">The Fortran-specific text is similarly suggestive, but it only says that a user can pass a simply contiguous array, not that such a thing is required.<br class=""><br class="">"In Fortran, one can pass the first element of a memory region or a whole array, which must be ‘simply contiguous’"<br class=""><br class="">Thanks,<br class=""><br class="">Jeff<br class=""><br class="">--<br class="">Jeff Hammond<br class=""><a href="mailto:jeff.science@gmail.com" class="">jeff.science@gmail.com</a><br class=""><a href="http://jeffhammond.github.io/" class="">http://jeffhammond.github.io/</a></div>
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