<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div>Hi Even,</div><div><br data-mce-bogus="1"></div><div>You write:</div><div><span style="color: #000000; font-family: arial, helvetica, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;" data-mce-style="color: #000000; font-family: arial, helvetica, sans-serif; font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: #ffffff; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">> There's no universal way however of knowing the X::Y target name for a random package. You have to consult each package's documentation.<span> </span></span><div style="clear: both;" data-mce-style="clear: both;"><br data-mce-bogus="1"></div></div><div>Where is this typically documented? For example, where can I find GDAL package documentation? I looked in the <a data-mce-href="https://gdal.org/gdal.pdf" href="https://gdal.org/gdal.pdf">main GDAL document</a> but didn't find it there (I might have missed it there...)</div><div><br data-mce-bogus="1"></div><div>Thanks!</div><div>Tom</div><div> </div><div data-marker="__SIG_PRE__">--------------------------------------------------<br>Thomas C. O'Reilly<br>Monterey Bay Aquarium Research Institute<br>7700 Sandholdt Road<br>Moss Landing, California 95039-9644<br>831-775-1766 (voice)<br>831-775-1620 (FAX)<br>oreilly@mbari.org (email)<br>http://www.mbari.org (World-wide Web)<br> <br>"The machine does not isolate us from the great mysteries<br> of nature, but plunges us more deeply into them."<br> <br> - ANTOINE DE SAINT-EXUPERY<br> "Wind, Sand, and Stars" (1939)<br> </div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"Even Rouault" <even.rouault@spatialys.com><br><b>To: </b>"Tom O'Reilly" <oreilly@mbari.org><br><b>Cc: </b>"gdal-dev" <gdal-dev@lists.osgeo.org><br><b>Sent: </b>Tuesday, June 7, 2022 10:10:26 AM<br><b>Subject: </b>Re: [gdal-dev] Why can't find_package(GDAL CONFIG) find GDAL_LIBRARIES?<br></div><div><br></div><div data-marker="__QUOTED_TEXT__"><p>That becomes slightly out-of-topic, but CMake practices have
evolved over time. Having depencies expressed from target name is
indeed more elegant/powerful. There's no universal way however of
knowing the X::Y target name for a random package. You have to
consult each package's documentation. One good reason is that the
same package can expose several targets (sub-components, shared vs
static, etc.)<br>
</p>
<div class="moz-cite-prefix">Le 07/06/2022 à 18:52, Tom O'Reilly a
écrit :<br>
</div>
<blockquote>
<div>
<div>Thanks for this information Even - very useful and
interesting.</div>
<div><br>
</div>
<div>I'm still a cmake newbie, and one cmake aspect that drives
me nuts is its "inconsistency" when it comes to finding
packages ("Should I call find_package(X) with MODULE or
CONFIG?", "Is it X_INCLUDE_DIRS or X_INCLUDES?"). So my
CMakeLists.txt tend to get complex pretty quickly. </div>
<div><br>
</div>
<div>The method you describe looks elegant and straightforward,
and it works for GDAL. In general for package 'X', is the
following *guaranteed* to produce a usable target of form
"X::X" or exit if package X is not found?</div>
<div><br>
</div>
<blockquote>
<div>#
Find package X</div>
<div>find_package(X CONFIG
REQUIRED)<br>
<div><br>
</div>
<div>
<p>add_executable(test_c
test_c.c)<br>
target_link_libraries(test_c PRIVATE X::X)</p>
</div>
</div>
<div><br>
</div>
</blockquote>
<div>If I could rely on that form, my CMakeLists.txt files would
be much simpler!</div>
<div><br>
</div>
<div>Thanks</div>
<div>Tom</div>
<div><br>
</div>
<div>--------------------------------------------------<br>
Thomas C. O'Reilly<br>
Monterey Bay Aquarium Research Institute<br>
7700 Sandholdt Road<br>
Moss Landing, California 95039-9644<br>
831-775-1766 (voice)<br>
831-775-1620 (FAX)<br>
<a href="mailto:oreilly@mbari.org" target="_blank" rel="nofollow noopener noreferrer">oreilly@mbari.org</a> (email)<br>
<a href="http://www.mbari.org" target="_blank" rel="nofollow noopener noreferrer">http://www.mbari.org</a> (World-wide Web)<br>
<br>
"The machine does not isolate us from the great mysteries<br>
of nature, but plunges us more deeply into them."<br>
<br>
- ANTOINE DE SAINT-EXUPERY<br>
"Wind, Sand, and Stars" (1939)<br>
</div>
<div><br>
</div>
<hr id="zwchr">
<div><b>From: </b>"Even Rouault"
<a href="mailto:even.rouault@spatialys.com" target="_blank" rel="nofollow noopener noreferrer"><even.rouault@spatialys.com></a><br>
<b>To: </b>"Tom O'Reilly" <a href="mailto:oreilly@mbari.org" target="_blank" rel="nofollow noopener noreferrer"><oreilly@mbari.org></a>,
"gdal-dev" <a href="mailto:gdal-dev@lists.osgeo.org" target="_blank" rel="nofollow noopener noreferrer"><gdal-dev@lists.osgeo.org></a><br>
<b>Sent: </b>Tuesday, June 7, 2022 12:28:42 AM<br>
<b>Subject: </b>Re: [gdal-dev] Why can't find_package(GDAL
CONFIG) find GDAL_LIBRARIES?<br>
</div>
<div><br>
</div>
<div>
<p>Tom,</p>
<p>GDAL_LIBRARIES and GDAL_INCLUDE_DIRS are indeed not
defined. You have to use the "GDAL::GDAL" target in a <br>
target_link_libraries() statement which propagates both
include and linking requirements and tends to be the modern
CMake practice, although admitedly not very clearly
documented in target_link_libraries() official
documentation. I found
<a href="https://schneide.blog/2016/04/08/modern-cmake-with-target_link_libraries/" rel="nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank">https://schneide.blog/2016/04/08/modern-cmake-with-target_link_libraries/</a>
which deal with that.<br>
</p>
<p>So a typical minimum CMakeLists.txt of a project using GDAL
is (this is actually
<a href="https://github.com/OSGeo/gdal/blob/master/autotest/postinstall/test_c/CMakeLists.txt" rel="nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank">https://github.com/OSGeo/gdal/blob/master/autotest/postinstall/test_c/CMakeLists.txt</a>
used in GDAL continuous integration to test usage of GDAL
from a third-party library/application)<br>
</p>
<p>"""<br>
</p>
<p>cmake_minimum_required(VERSION 3.0)<br>
<br>
project(test_c C CXX) # CXX for properly linking GDAL<br>
<br>
find_package(GDAL CONFIG REQUIRED)<br>
<br>
add_executable(test_c test_c.c)<br>
target_link_libraries(test_c PRIVATE GDAL::GDAL)</p>
<p>"""</p>
<p>I've created <a href="https://github.com/OSGeo/gdal/issues/5875" rel="nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank">https://github.com/OSGeo/gdal/issues/5875</a>
to track we need documenting that.</p>
<p>Note: If you really wanted to get the equivalent of
GDAL_INCLUDE_DIRS and GDAL_LIBRARIES, you could use the
following expressions:<br>
</p>
<p>$<TARGET_PROPERTY:GDAL::GDAL,INTERFACE_INCLUDE_DIRECTORIES></p>
<p>$<TARGET_PROPERTY:GDAL::GDAL,INTERFACE_LINK_LIBRARIES></p>
<p><br>
</p>
<p>Even<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">Le 07/06/2022 à 02:02, Tom
O'Reilly a écrit :<br>
</div>
<blockquote>
<div>
<div>I've just built and installed GDAL 3.5.0 on ubuntu
20.04, with cmake 3.5.0 and make. It appears that 'make
install' installs needed cmake config files for GDAL:</div>
<div>
<blockquote>
<div>-- Installing:
/usr/local/lib/x86_64-linux-gnu/cmake/gdal/GDALConfigVersion.cmake</div>
<div>-- Installing:
/usr/local/lib/x86_64-linux-gnu/cmake/gdal/GDALConfig.cmake</div>
</blockquote>
</div>
<div>I'm building my own project that uses GDAL. The
CMakelists.txt invokes find_package() and prints out
resulting variables:</div>
<div>
<blockquote>
<div>find_package(GDAL CONFIG REQUIRED)</div>
<div><br>
</div>
<div>if (GDAL_FOUND)</div>
<div> message("GDAL Found!")</div>
<div> message("GDAL_INCLUDE_DIRS:
${GDAL_INCLUDE_DIRS}")</div>
<div> message("GDAL_LIBRARIES: ${GDAL_LIBRARIES}")</div>
<div> message("GDAL_VERSION: ${GDAL_VERSION}")</div>
<div>else()</div>
<div> message("GDAL not found")</div>
<div>endif()</div>
</blockquote>
<div>Running cmake indicates that GDAL_FOUND is true,
GDAL_VERSION is set to the expected value(3.5.0), but
GDAL_LIBRARIES and GDAL_INCLUDE_DIRS are empty:</div>
<div>
<blockquote>
<div>GDAL Found!</div>
<div>GDAL_INCLUDE_DIRS: </div>
<div>GDAL_LIBRARIES: </div>
<div>GDAL_LIBRARY: </div>
<div>GDAL_VERSION: 3.5.0</div>
</blockquote>
</div>
<div>Why are GDAL_LIBRARIES and GDAL_INCLUDE_DIR empty?<br>
</div>
<div><br>
</div>
<div>Thanks</div>
<div>Tom</div>
<div><br>
</div>
<blockquote>
<div><br>
</div>
</blockquote>
</div>
<div><br>
</div>
<div>--------------------------------------------------<br>
Thomas C. O'Reilly<br>
Monterey Bay Aquarium Research Institute<br>
7700 Sandholdt Road<br>
Moss Landing, California 95039-9644<br>
831-775-1766 (voice)<br>
831-775-1620 (FAX)<br>
<a href="mailto:oreilly@mbari.org" rel="nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank">oreilly@mbari.org</a>
(email)<br>
<a href="http://www.mbari.org" rel="nofollow noopener noreferrer nofollow noopener noreferrer" target="_blank">http://www.mbari.org</a>
(World-wide Web)<br>
<br>
"The machine does not isolate us from the great
mysteries<br>
of nature, but plunges us more deeply into them."<br>
<br>
- ANTOINE DE SAINT-EXUPERY<br>
"Wind, Sand, and Stars" (1939)<br>
</div>
</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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