1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
|
<!DOCTYPE html>
<html class="writer-html5" lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>3.4. Compiler Notes — Open MPI 5.0.8 documentation</title>
<link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
<link rel="stylesheet" type="text/css" href="../_static/css/theme.css" />
<!--[if lt IE 9]>
<script src="../_static/js/html5shiv.min.js"></script>
<![endif]-->
<script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
<script src="../_static/jquery.js"></script>
<script src="../_static/underscore.js"></script>
<script src="../_static/_sphinx_javascript_frameworks_compat.js"></script>
<script src="../_static/doctools.js"></script>
<script src="../_static/sphinx_highlight.js"></script>
<script src="../_static/js/theme.js"></script>
<link rel="index" title="Index" href="../genindex.html" />
<link rel="search" title="Search" href="../search.html" />
<link rel="next" title="3.5. General Run-Time Support Notes" href="run-time.html" />
<link rel="prev" title="3.3. Platform Notes" href="platform.html" />
</head>
<body class="wy-body-for-nav">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-scroll">
<div class="wy-side-nav-search" >
<a href="../index.html" class="icon icon-home">
Open MPI
</a>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
<input type="text" name="q" placeholder="Search docs" aria-label="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div><div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="Navigation menu">
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="../quickstart.html">1. Quick start</a></li>
<li class="toctree-l1"><a class="reference internal" href="../getting-help.html">2. Getting help</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="index.html">3. Release notes</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="changelog/index.html">3.1. Changelog</a></li>
<li class="toctree-l2"><a class="reference internal" href="general.html">3.2. General notes</a></li>
<li class="toctree-l2"><a class="reference internal" href="platform.html">3.3. Platform Notes</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">3.4. Compiler Notes</a></li>
<li class="toctree-l2"><a class="reference internal" href="run-time.html">3.5. General Run-Time Support Notes</a></li>
<li class="toctree-l2"><a class="reference internal" href="mpi.html">3.6. MPI Functionality and Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="openshmem.html">3.7. OpenSHMEM Functionality and Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="mpi-collectives.html">3.8. MPI Collectives</a></li>
<li class="toctree-l2"><a class="reference internal" href="openshmem-collectives.html">3.9. OpenSHMEM Collectives</a></li>
<li class="toctree-l2"><a class="reference internal" href="networks.html">3.10. Network Support</a></li>
<li class="toctree-l2"><a class="reference internal" href="extensions.html">3.11. Open MPI Extensions</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="../installing-open-mpi/index.html">4. Building and installing Open MPI</a></li>
<li class="toctree-l1"><a class="reference internal" href="../features/index.html">5. Open MPI-specific features</a></li>
<li class="toctree-l1"><a class="reference internal" href="../validate.html">6. Validating your installation</a></li>
<li class="toctree-l1"><a class="reference internal" href="../version-numbering.html">7. Version numbers and compatibility</a></li>
<li class="toctree-l1"><a class="reference internal" href="../mca.html">8. The Modular Component Architecture (MCA)</a></li>
<li class="toctree-l1"><a class="reference internal" href="../building-apps/index.html">9. Building MPI applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../launching-apps/index.html">10. Launching MPI applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../tuning-apps/index.html">11. Run-time operation and tuning MPI applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../app-debug/index.html">12. Debugging Open MPI Parallel Applications</a></li>
<li class="toctree-l1"><a class="reference internal" href="../developers/index.html">13. Developer’s guide</a></li>
<li class="toctree-l1"><a class="reference internal" href="../contributing.html">14. Contributing to Open MPI</a></li>
<li class="toctree-l1"><a class="reference internal" href="../license/index.html">15. License</a></li>
<li class="toctree-l1"><a class="reference internal" href="../history.html">16. History of Open MPI</a></li>
<li class="toctree-l1"><a class="reference internal" href="../man-openmpi/index.html">17. Open MPI manual pages</a></li>
<li class="toctree-l1"><a class="reference internal" href="../man-openshmem/index.html">18. OpenSHMEM manual pages</a></li>
</ul>
</div>
</div>
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap"><nav class="wy-nav-top" aria-label="Mobile navigation menu" >
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="../index.html">Open MPI</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="Page navigation">
<ul class="wy-breadcrumbs">
<li><a href="../index.html" class="icon icon-home" aria-label="Home"></a></li>
<li class="breadcrumb-item"><a href="index.html"><span class="section-number">3. </span>Release notes</a></li>
<li class="breadcrumb-item active"><span class="section-number">3.4. </span>Compiler Notes</li>
<li class="wy-breadcrumbs-aside">
<a href="../_sources/release-notes/compilers.rst.txt" rel="nofollow"> View page source</a>
</li>
</ul>
<hr/>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<style>
.wy-table-responsive table td,.wy-table-responsive table th{white-space:normal}
</style><div class="section" id="compiler-notes">
<span id="compiler-notes-section-label"></span><h1><span class="section-number">3.4. </span>Compiler Notes<a class="headerlink" href="#compiler-notes" title="Permalink to this heading"></a></h1>
<ul>
<li><p>Open MPI requires a C99-capable compiler to build.</p></li>
<li><p>On platforms other than x86-64, AArc64 (64-bit ARM), and PPC, Open
MPI requires a compiler that either supports C11 atomics or the GCC
<code class="docutils literal notranslate"><span class="pre">__atomic</span></code> atomics (e.g., GCC >= v4.8.x).</p></li>
<li><p>32-bit platforms are only supported with a recent compiler that
supports C11 atomics. This includes GCC 4.9.x+ (although GCC 6.x or
newer is recommended), the Intel compiler suite 16, and clang 3.1.</p></li>
<li><p>Mixing compilers from different vendors when building Open MPI
(e.g., using the C/C++ compiler from one vendor and the Fortran
compiler from a different vendor) has been successfully employed by
some Open MPI users (discussed on the Open MPI user’s mailing list),
but such configurations are not tested and not documented. For
example, such configurations may require additional compiler /
linker flags to make Open MPI build properly.</p>
<p>A not-uncommon case for this is when building on MacOS with the
system-default GCC compiler (i.e., <code class="docutils literal notranslate"><span class="pre">/usr/bin/gcc</span></code>), but a 3rd party
gfortran (e.g., provided by Homebrew, in <code class="docutils literal notranslate"><span class="pre">/usr/local/bin/gfortran</span></code>).
Since these compilers are provided by different organizations, they
have different default search paths. For example, if Homebrew has
also installed a local copy of Libevent (a 3rd party package that
Open MPI requires), the MacOS-default <code class="docutils literal notranslate"><span class="pre">gcc</span></code> linker will find it
without any additional command line flags, but the Homebrew-provided
gfortran linker will not. In this case, it may be necessary to
provide the following on the configure command line:</p>
<div class="highlight-sh notranslate"><div class="highlight"><pre><span></span>shell$<span class="w"> </span>./configure<span class="w"> </span><span class="nv">FCFLAGS</span><span class="o">=</span>-L/usr/local/lib<span class="w"> </span>...
</pre></div>
</div>
<p>This <code class="docutils literal notranslate"><span class="pre">-L</span></code> flag will then be passed to the Fortran linker when
creating Open MPI’s Fortran libraries, and it will therefore be able
to find the installed Libevent.</p>
</li>
<li><p>In general, the latest versions of compilers of a given vendor’s
series have the least bugs. We have seen cases where Vendor XYZ’s
compiler version A.B fails to compile Open MPI, but version A.C
(where C>B) works just fine. If you run into a compile failure, you
might want to double check that you have the latest bug fixes and
patches for your compiler.</p></li>
<li><p>Users have reported issues with older versions of the Fortran PGI
compiler suite when using Open MPI’s (non-default) <code class="docutils literal notranslate"><span class="pre">--enable-debug</span></code>
configure option. Per the above advice of using the most recent
version of a compiler series, the Open MPI team recommends using the
latest version of the PGI suite, and/or not using the <code class="docutils literal notranslate"><span class="pre">--enable-debug</span></code>
configure option. If it helps, here’s what we have found with some
(not comprehensive) testing of various versions of the PGI compiler
suite:</p>
<ul class="simple">
<li><p>pgi-8 : NO known good version with <code class="docutils literal notranslate"><span class="pre">--enable-debug</span></code></p></li>
<li><p>pgi-9 : 9.0-4 known GOOD</p></li>
<li><p>pgi-10: 10.0-0 known GOOD</p></li>
<li><p>pgi-11: NO known good version with <code class="docutils literal notranslate"><span class="pre">--enable-debug</span></code></p></li>
<li><p>pgi-12: 12.10 known BAD with <code class="docutils literal notranslate"><span class="pre">-m32</span></code>, but known GOOD without <code class="docutils literal notranslate"><span class="pre">-m32</span></code>
(and 12.8 and 12.9 both known BAD with <code class="docutils literal notranslate"><span class="pre">--enable-debug</span></code>)</p></li>
<li><p>pgi-13: 13.9 known BAD with <code class="docutils literal notranslate"><span class="pre">-m32</span></code>, 13.10 known GOOD without <code class="docutils literal notranslate"><span class="pre">-m32</span></code></p></li>
<li><p>pgi-15: 15.10 known BAD with <code class="docutils literal notranslate"><span class="pre">-m32</span></code></p></li>
</ul>
</li>
<li><p>Similarly, there is a known Fortran PGI compiler issue with long
source directory path names that was resolved in 9.0-4 (9.0-3 is
known to be broken in this regard).</p></li>
<li><p>Open MPI does not support the PGI compiler suite on OS X or MacOS.
See issues below for more details:</p>
<ul class="simple">
<li><p><a class="reference external" href="https://github.com/open-mpi/ompi/issues/2604">https://github.com/open-mpi/ompi/issues/2604</a></p></li>
<li><p><a class="reference external" href="https://github.com/open-mpi/ompi/issues/2605">https://github.com/open-mpi/ompi/issues/2605</a></p></li>
</ul>
</li>
<li><p>OpenSHMEM Fortran bindings do not support the “no underscore”
Fortran symbol convention. IBM’s <code class="docutils literal notranslate"><span class="pre">xlf</span></code> compilers build in that mode
by default. As such, IBM’s <code class="docutils literal notranslate"><span class="pre">xlf</span></code> compilers cannot build/link the
OpenSHMEM Fortran bindings by default. A workaround is to pass
<code class="docutils literal notranslate"><span class="pre">FC="xlf</span> <span class="pre">-qextname"</span></code> at configure time to force a trailing
underscore. See <a class="reference external" href="https://github.com/open-mpi/ompi/issues/3612">https://github.com/open-mpi/ompi/issues/3612</a> for
more details.</p></li>
<li><p>MPI applications that use the <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module on PowerPC platforms
(tested ppc64le) will likely experience runtime failures if:</p>
<blockquote>
<div><ul class="simple">
<li><p>they are using a GNU linker (ld) version after v2.25.1 and before
v2.28,
<em>and</em></p></li>
<li><p>they compiled with PGI (tested 17.5) or XL (tested v15.1.5)
compilers. This was noticed on Ubuntu 16.04 which uses the
2.26.1 version of <code class="docutils literal notranslate"><span class="pre">ld</span></code> by default. However, this issue impacts
any OS using a version of <code class="docutils literal notranslate"><span class="pre">ld</span></code> noted above. This GNU linker
regression will be fixed in version 2.28. <a class="reference external" href="https://sourceware.org/bugzilla/show_bug.cgi?id=21306">Here is a link to the
GNU bug on this issue</a>. The
XL compiler will include a fix for this issue in a future
release.</p></li>
</ul>
</div></blockquote>
</li>
<li><p>On NetBSD-6 (at least AMD64 and i386), and possibly on OpenBSD,
Libtool misidentifies properties of f95/g95, leading to obscure
compile-time failures if used to build Open MPI. You can work
around this issue by ensuring that libtool will not use f95/g95
(e.g., by specifying <code class="docutils literal notranslate"><span class="pre">FC=<some_other_compiler></span></code>, or otherwise ensuring
a different Fortran compiler will be found earlier in the path than
<code class="docutils literal notranslate"><span class="pre">f95</span></code>/<code class="docutils literal notranslate"><span class="pre">g95</span></code>), or by disabling the Fortran MPI bindings with
<code class="docutils literal notranslate"><span class="pre">--disable-mpi-fortran</span></code>.</p></li>
<li><p>On OpenBSD/i386, if you configure with
<code class="docutils literal notranslate"><span class="pre">--enable-mca-no-build=patcher</span></code>, you will also need to add
<code class="docutils literal notranslate"><span class="pre">--disable-dlopen</span></code>. Otherwise, odd crashes can occur
nondeterministically.</p></li>
<li><p>Absoft 11.5.2 plus a service pack from September 2012 (which Absoft
says is available upon request), or a version later than 11.5.2
(e.g., 11.5.3), is required to compile the Fortran <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code>
module.</p></li>
<li><p>Open MPI does not support the Sparc v8 CPU target. However,
as of Solaris Studio 12.1, and later compilers, one should not
specify <code class="docutils literal notranslate"><span class="pre">-xarch=v8plus</span></code> or <code class="docutils literal notranslate"><span class="pre">-xarch=v9</span></code>. The use of the options
<code class="docutils literal notranslate"><span class="pre">-m32</span></code> and <code class="docutils literal notranslate"><span class="pre">-m64</span></code> for producing 32 and 64 bit targets, respectively,
are now preferred by the Solaris Studio compilers. GCC may
require either <code class="docutils literal notranslate"><span class="pre">-m32</span></code> or <code class="docutils literal notranslate"><span class="pre">-mcpu=v9</span> <span class="pre">-m32</span></code>, depending on GCC version.</p></li>
<li><p>If one tries to build OMPI on Ubuntu with Solaris Studio using the C++
compiler and the <code class="docutils literal notranslate"><span class="pre">-m32</span></code> option, you might see a warning:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>CC: Warning: failed to detect system linker version, falling back to custom linker usage
</pre></div>
</div>
<p>And the build will fail. One can overcome this error by either
setting <code class="docutils literal notranslate"><span class="pre">LD_LIBRARY_PATH</span></code> to the location of the 32 bit libraries
(most likely <code class="docutils literal notranslate"><span class="pre">/lib32</span></code>), or giving <code class="docutils literal notranslate"><span class="pre">LDFLAGS="-L/lib32</span> <span class="pre">-R/lib32"</span></code>
to the <code class="docutils literal notranslate"><span class="pre">configure</span></code> command. Officially, Solaris Studio is not
supported on Ubuntu Linux distributions, so additional problems
might occur.</p>
</li>
<li><p>Open MPI does not support the <code class="docutils literal notranslate"><span class="pre">gccfss</span></code> compiler (GCC For SPARC
Systems; a now-defunct compiler project from Sun).</p></li>
<li><p>At least some versions of the Intel 8.1 compiler seg fault while
compiling certain Open MPI source code files. As such, it is not
supported.</p></li>
<li><p>It has been reported that the Intel 9.1 and 10.0 compilers fail to
compile Open MPI on IA64 platforms. As of 12 Sep 2012, there is
very little (if any) testing performed on IA64 platforms (with any
compiler). Support is “best effort” for these platforms, but it is
doubtful that any effort will be expended to fix the Intel 9.1 /
10.0 compiler issuers on this platform.</p></li>
<li><p>Early versions of the Intel 12.1 Linux compiler suite on x86_64 seem
to have a bug that prevents Open MPI from working. Symptoms
including immediate segv of the wrapper compilers (e.g., <code class="docutils literal notranslate"><span class="pre">mpicc</span></code>) and
MPI applications. As of 1 Feb 2012, if you upgrade to the latest
version of the Intel 12.1 Linux compiler suite, the problem will go
away.</p></li>
<li><p><a class="reference external" href="https://github.com/open-mpi/ompi/issues/7615">Users have reported</a> that the Intel
Fortran compiler will fail to link Fortran-based MPI applications on
macOS with linker errors similar to this:</p>
<div class="highlight-text notranslate"><div class="highlight"><pre><span></span>Undefined symbols for architecture x86_64:
"_ompi_buffer_detach_f08", referenced from:
import-atom in libmpi_usempif08.dylib
ld: symbol(s) not found for architecture x86_64
</pre></div>
</div>
<p>It appears that setting the environment variable
<code class="docutils literal notranslate"><span class="pre">lt_cx_ld_force_load=no</span></code> before invoking Open MPI’s <code class="docutils literal notranslate"><span class="pre">configure</span></code>
script works around the issue. For example:</p>
<div class="highlight-sh notranslate"><div class="highlight"><pre><span></span>shell$<span class="w"> </span><span class="nv">lt_cv_ld_force_load</span><span class="o">=</span>no<span class="w"> </span>./configure<span class="w"> </span>...
</pre></div>
</div>
</li>
<li><p>The Portland Group compilers prior to version 7.0 require the
<code class="docutils literal notranslate"><span class="pre">-Msignextend</span></code> compiler flag to extend the sign bit when converting
from a shorter to longer integer. This is different than other
compilers (such as GNU). When compiling Open MPI with the Portland
compiler suite, the following flags should be passed to Open MPI’s
<code class="docutils literal notranslate"><span class="pre">configure</span></code> script:</p>
<div class="highlight-sh notranslate"><div class="highlight"><pre><span></span>shell$<span class="w"> </span>./configure<span class="w"> </span><span class="nv">CFLAGS</span><span class="o">=</span>-Msignextend<span class="w"> </span><span class="nv">CXXFLAGS</span><span class="o">=</span>-Msignextend<span class="w"> </span><span class="se">\</span>
<span class="w"> </span>--with-wrapper-cflags<span class="o">=</span>-Msignextend<span class="w"> </span><span class="se">\</span>
<span class="w"> </span>--with-wrapper-cxxflags<span class="o">=</span>-Msignextend<span class="w"> </span>...
</pre></div>
</div>
<p>This will both compile Open MPI with the proper compile flags and
also automatically add <code class="docutils literal notranslate"><span class="pre">-Msignextend</span></code> when the C and C++ MPI wrapper
compilers are used to compile user MPI applications.</p>
</li>
<li><p>It has been reported that Pathscale 5.0.5 and 6.0.527 compilers
give an internal compiler error when trying to build Open MPI.</p></li>
<li><p>As of July 2017, the Pathscale compiler suite apparently has no
further commercial support, and it does not look like there will be
further releases. Any issues discovered regarding building /
running Open MPI with the Pathscale compiler suite therefore may not
be able to be resolved.</p></li>
<li><p>Using the Absoft compiler to build the MPI Fortran bindings on Suse
9.3 is known to fail due to a Libtool compatibility issue.</p></li>
<li><p>There is now only a single Fortran MPI wrapper compiler and a
single Fortran OpenSHMEM wrapper compiler: <code class="docutils literal notranslate"><span class="pre">mpifort</span></code> and <code class="docutils literal notranslate"><span class="pre">oshfort</span></code>,
respectively.</p>
<div class="admonition caution">
<p class="admonition-title">Caution</p>
<p>The legacy executable names <code class="docutils literal notranslate"><span class="pre">mpif77</span></code> and <code class="docutils literal notranslate"><span class="pre">mpif90</span></code>
still exist, but they are symbolic links to
<code class="docutils literal notranslate"><span class="pre">mpifort</span></code>. Users should immediately stop using the
legacy names, and should always use <code class="docutils literal notranslate"><span class="pre">mpifort</span></code>.</p>
</div>
<p>Similarly, Open MPI’s <code class="docutils literal notranslate"><span class="pre">configure</span></code> script only recognizes the <code class="docutils literal notranslate"><span class="pre">FC</span></code>
and <code class="docutils literal notranslate"><span class="pre">FCFLAGS</span></code> environment variables (to specify the Fortran
compiler and compiler flags, respectively). The <code class="docutils literal notranslate"><span class="pre">F77</span></code> and <code class="docutils literal notranslate"><span class="pre">FFLAGS</span></code>
environment variables are <strong>IGNORED</strong>.</p>
<div class="admonition important">
<p class="admonition-title">Important</p>
<p>As a direct result, it is <strong>STRONGLY</strong> recommended
that you specify a Fortran compiler that uses file suffixes to
determine Fortran code layout (e.g., free form vs. fixed). For
example, with some versions of the IBM XLF compiler, it is
preferable to use <code class="docutils literal notranslate"><span class="pre">FC=xlf</span></code> instead of <code class="docutils literal notranslate"><span class="pre">FC=xlf90</span></code>, because
<code class="docutils literal notranslate"><span class="pre">xlf</span></code> will automatically determine the difference between free
form and fixed Fortran source code.</p>
</div>
<p>However, many Fortran compilers allow specifying additional
command-line arguments to indicate which Fortran dialect to use.
For example, if <code class="docutils literal notranslate"><span class="pre">FC=xlf90</span></code>, you may need to use <code class="docutils literal notranslate"><span class="pre">mpifort</span> <span class="pre">--qfixed</span> <span class="pre">...</span></code>
to compile fixed format Fortran source files.</p>
<p>You can use either <code class="docutils literal notranslate"><span class="pre">ompi_info</span></code> or <code class="docutils literal notranslate"><span class="pre">oshmem_info</span></code> to see with which
Fortran compiler Open MPI was configured and compiled.</p>
<p>There are up to three sets of Fortran MPI bindings that may be
provided (depending on your Fortran compiler):</p>
<ol class="arabic simple">
<li><p><code class="docutils literal notranslate"><span class="pre">mpif.h</span></code>: This is the first MPI Fortran interface that was
defined in MPI-1. It is a file that is included in Fortran
source code. The only interface declared in Open MPI’s
<code class="docutils literal notranslate"><span class="pre">mpif.h</span></code> is <code class="docutils literal notranslate"><span class="pre">MPI_SIZEOF</span></code> (because of its polymorphism). All
other interfaces are implicit.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">mpi</span></code> module: The <code class="docutils literal notranslate"><span class="pre">mpi</span></code> module file was added in MPI-2. It
provides strong compile-time parameter type checking for MPI all
interfaces.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module: The <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module was added in MPI-3.
It provides many advantages over the <code class="docutils literal notranslate"><span class="pre">mpif.h</span></code> file and <code class="docutils literal notranslate"><span class="pre">mpi</span></code>
module. For example, MPI handles have distinct types (vs. all
being integers). See the <a class="reference external" href="https://www.mpi-forum.org/docs/">MPI-3.0 (or later) standard</a> for more details.</p></li>
</ol>
<div class="admonition important">
<p class="admonition-title">Important</p>
<p>The <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module is <strong>STRONGLY</strong> recommended
for all new MPI Fortran subroutines and applications. Note that
the <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module can be used in conjunction with the other
two Fortran MPI bindings in the same application (only one
binding can be used per subroutine/function, however). Full
interoperability between <code class="docutils literal notranslate"><span class="pre">mpif.h</span></code>/<code class="docutils literal notranslate"><span class="pre">mpi</span></code> module and
<code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module MPI handle types is provided, allowing
<code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> to be used in new subroutines in legacy MPI
applications.</p>
</div>
<p>Per the OpenSHMEM specification, there is only one Fortran OpenSHMEM
binding provided:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">shmem.fh</span></code>: All Fortran OpenSHMEM programs should include
<code class="docutils literal notranslate"><span class="pre">shmem.f</span></code>, and Fortran OpenSHMEM programs that use constants
defined by OpenSHMEM <strong>MUST</strong> include <code class="docutils literal notranslate"><span class="pre">shmem.fh</span></code>.</p></li>
</ul>
<p>The following notes apply to the above-listed Fortran bindings:</p>
<ul>
<li><p>All Fortran compilers support the <code class="docutils literal notranslate"><span class="pre">mpif.h</span></code>/<code class="docutils literal notranslate"><span class="pre">shmem.fh</span></code>-based
bindings, with one exception: the <code class="docutils literal notranslate"><span class="pre">MPI_SIZEOF</span></code> interfaces will
only be present when Open MPI is built with a Fortran compiler
that supports the <code class="docutils literal notranslate"><span class="pre">INTERFACE</span></code> keyword and <code class="docutils literal notranslate"><span class="pre">ISO_FORTRAN_ENV</span></code>. Most
notably, this excludes the GNU Fortran compiler suite before
version 4.9.</p></li>
<li><p>The level of support provided by the <code class="docutils literal notranslate"><span class="pre">mpi</span></code> module is based on your
Fortran compiler.</p>
<p>If Open MPI is built with a non-GNU Fortran compiler, or if Open
MPI is built with the GNU Fortran compiler >= v4.9, all MPI
subroutines will be prototyped in the <code class="docutils literal notranslate"><span class="pre">mpi</span></code> module. All calls to
MPI subroutines will therefore have their parameter types checked
at compile time.</p>
<p>If Open MPI is built with an old <code class="docutils literal notranslate"><span class="pre">gfortran</span></code> (i.e., < v4.9), a
limited <code class="docutils literal notranslate"><span class="pre">mpi</span></code> module will be built. Due to the limitations of
these compilers, and per guidance from the MPI-3.0 (and later)
specification, all MPI subroutines with “choice” buffers are
specifically <em>not</em> included in the <code class="docutils literal notranslate"><span class="pre">mpi</span></code> module, and their
parameters will not be checked at compile time. Specifically, all
MPI subroutines with no “choice” buffers are prototyped and will
receive strong parameter type checking at run-time (e.g.,
<code class="docutils literal notranslate"><span class="pre">MPI_INIT</span></code>, <code class="docutils literal notranslate"><span class="pre">MPI_COMM_RANK</span></code>, etc.).</p>
<p>Similar to the <code class="docutils literal notranslate"><span class="pre">mpif.h</span></code> interface, <code class="docutils literal notranslate"><span class="pre">MPI_SIZEOF</span></code> is only
supported on Fortran compilers that support <code class="docutils literal notranslate"><span class="pre">INTERFACE</span></code> and
<code class="docutils literal notranslate"><span class="pre">ISO_FORTRAN_ENV</span></code>.</p>
</li>
<li><p>The <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module has been tested with the Intel Fortran
compiler and gfortran >= 4.9. Other modern Fortran compilers
likely also work.</p>
<p>Many older Fortran compilers do not provide enough modern Fortran
features to support the <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module. For example, <code class="docutils literal notranslate"><span class="pre">gfortran</span></code>
< v4.9 does provide enough support for the <code class="docutils literal notranslate"><span class="pre">mpi_f08</span></code> module.</p>
</li>
</ul>
<p>You can examine the output of the following command to see all
the Fortran features that are/are not enabled in your Open MPI
installation:</p>
<div class="highlight-sh notranslate"><div class="highlight"><pre><span></span>shell$<span class="w"> </span>ompi_info<span class="w"> </span><span class="p">|</span><span class="w"> </span>grep<span class="w"> </span>-i<span class="w"> </span>fort
</pre></div>
</div>
</li>
</ul>
</div>
</div>
</div>
<footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer">
<a href="platform.html" class="btn btn-neutral float-left" title="3.3. Platform Notes" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a>
<a href="run-time.html" class="btn btn-neutral float-right" title="3.5. General Run-Time Support Notes" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
</div>
<hr/>
<div role="contentinfo">
<p>© Copyright 2003-2025, The Open MPI Community.
<span class="lastupdated">Last updated on 2025-05-30 16:41:43 UTC.
</span></p>
</div>
Built with <a href="https://www.sphinx-doc.org/">Sphinx</a> using a
<a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a>
provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script>
jQuery(function () {
SphinxRtdTheme.Navigation.enable(true);
});
</script>
</body>
</html>
|
