Nik,
You can definitely use dynamic linking in an iOS app.

I don’t know how you would do that in CMake.

John Daniel
Etresoft, Inc.

On Jul 3, 2022, at 9:17 PM, Nik Sands <n...@nixanz.com> wrote:

 Hi Even,

Thanks for the suggestions.  I am now using '$HOME' instead of ‘~’.  I’m using 
static libraries instead of dynamic libraries because my goal is to build GDAL 
for iOS once I get the process working for macOS and my understanding is that I 
cannot use dynamic linking in an iOS app (except for OS-bundled libraries).

I’ve now attempted to build this way (using custom-built SQLite, as explained 
earlier):

cd gdal-{VERSION}
rm -r build
mkdir build
cd build
cmake -DSQLITE3_INCLUDE_DIR=$HOME/build/include 
-DSQLITE3_LIBRARY=$HOME/build/lib/libsqlite3.a 
-DCMAKE_INSTALL_PREFIX=$HOME/build -DCMAKE_BUILD_TYPE=Release .. >log.txt 2>&1

I found that it fails if I don’t include:  -DCMAKE_BUILD_TYPE=Release

Ignoring the CMake error log, as advised, and now just scanning sdout and 
stderr instead, I find that I get the following at about half-way through the 
output:

==========
-- Found BISON: /usr/bin/bison (found version "2.3")
Traceback (most recent call last):
  File 
"/Users/nsands/Documents/Development/3rdParty/GDAL3/gdal-3.5.0/build/swig/python/get_suffix.py",
 line 1, in <module>
    from setuptools.command.build_ext import EXTENSION_SUFFIXES; 
print(EXTENSION_SUFFIXES[0])
ImportError: cannot import name 'EXTENSION_SUFFIXES'
--   Target system:             Darwin
==========

I don’t really know where to go from here.

Cheers,
Nik.

On 1 Jul 2022, at 7:22 pm, Even Rouault 
<even.roua...@spatialys.com<mailto:even.roua...@spatialys.com>> wrote:

Nik,

regarding the build isssue with Mac system sqlite3, I've filed this as 
https://github.com/OSGeo/gdal/issues/6011

regarding your other  "Configuring incomplete, errors occurred!" issue, I've 
found that generally the CMakeOutput.log and CMakeError.log files aren't the 
best way to spot the issue. They contain a lot of "normal" errors such as the 
one with iconv, that are due to trying to detect features available or not 
available in the build environment, so it is expected that some detections 
fail. You must have another issue, which is in the standard error stream of the 
"cmake" invokation

Run "cmake .. 2>&1 >log.txt" and look for "error" in log.txt

You may also want to try to link to the dynamic library of libsqlite3 rather 
than the static one (static linking is always more difficult to accomplish), so 
something like -DSQLITE3_LIBRARY=$HOME/build/lib/libsqlite3.dylib

I would also avoid using the '~' character for values of CMake variables and 
rather use $HOME. On my Linux shell, I see the values in the CMakeCache.txt are 
not expanded to full paths, and I doubt CMake will do it by itself.

Even

Le 01/07/2022 à 10:58, Nik Sands a écrit :
Thanks again for all the replies and advice.  I should have provided more 
context around my initial query about building GDAL with cmake on macOS.  So 
here goes… (this is quite long, so bear with me…)

My ultimate aim is to build GDAL 3.6 (not yet released) for iOS on ARM (as well 
as for macOS on Intel).  I can then combine them into a fat library and use 
that in my project (which is what I've been doing successfully for GDAL 2.2.2 
for some time).  GDAL 3.6 isn't yet released, so I'm working with 3.5 for now 
in order to get my build process right.

I believe that for iOS, I cannot use any 'homebrew' or 'macports' packages 
installed in /usr/local, etc, as dependencies for the GDAL build.  They will 
likely work for macOS, but not for iOS.  Therefore I will need to build any 
dependencies manually and install to another location (for both iOS and macOS), 
where they do not already exist in the standard macOS/iOS SDK locations (or 
where the Apple-supplied libraries in those SDK locations are otherwise 
incompatible with GDAL - see SQLite notes below).  For any such dependencies, I 
plan to install them in ~/build (as I did previously for GDAL 2.2.2).

So I'm starting out building simply for macOS, but trying to use a similar 
technique to what I hope to use for iOS (after I get it working for macOS).

So with all that background, I will now start at the beginning of my attempts 
to build GDAL 3.5 using a method that I hope will also work for iOS...

The GDAL cmake hints page says to do this:

cd gdal-{VERSION}
mkdir build
cd build
cmake ..
cmake --build .
cmake --build . --target install

When I run this as-is, the 'cmake ..' succeeds, but the 'cmake --build .' fails 
at the 82% mark with this output:

==========
[ 82%] Building CXX object 
ogr/ogrsf_frmts/sqlite/CMakeFiles/ogr_SQLite.dir/ogrsqlitedatasource.cpp.o
/Users/nsands/Documents/Development/3rdParty/GDAL3/gdal-3.5.0/ogr/ogrsf_frmts/sqlite/ogrsqlitedatasource.cpp:733:21:
 error: use of undeclared identifier 'sqlite3_enable_load_extension'
                if( sqlite3_enable_load_extension(hDB, 1) == SQLITE_OK )
                    ^
/Users/nsands/Documents/Development/3rdParty/GDAL3/gdal-3.5.0/ogr/ogrsf_frmts/sqlite/ogrsqlitedatasource.cpp:746:21:
 error: use of undeclared identifier 'sqlite3_load_extension'
                if( sqlite3_load_extension(hDB, aosExtensions[i], nullptr, 
&pszErrMsg) != SQLITE_OK )
                    ^
2 errors generated.
make[2]: *** 
[ogr/ogrsf_frmts/sqlite/CMakeFiles/ogr_SQLite.dir/ogrsqlitedatasource.cpp.o] 
Error 1
make[1]: *** [ogr/ogrsf_frmts/sqlite/CMakeFiles/ogr_SQLite.dir/all] Error 2
make: *** [all] Error 2
==========

So I then build SQLite manually, including the requirements that the built-in 
macOS SQLite seems to be missing, and install to ~/build.  Ie,

./configure SQLITE_ENABLE_RTREE=1 --prefix=/Users/{USERNAME}/build

Then I attempt to GDAL again as follows:

cd gdal-{VERSION}
rm -r build
mkdir build
cd build
cmake -DSQLITE3_INCLUDE_DIR=~/build/include 
-DSQLITE3_LIBRARY=~/build/lib/libsqlite3.a ..


Now cmake fails with:

-- Configuring incomplete, errors occurred!
See also "...../CMakeOutput.log".
See also "...../CMakeError.log".

The error log is fairly long, but two errors near the beginning seem to be 
perhaps quite significant:

ld: library not found for -lSystem

and a bit further on:

ld: library not found for -lc++

and then skipping to the end of the error log:

==========
/Users/nsands/Documents/Development/3rdParty/GDAL3/gdal-3.5.0/build/CMakeFiles/CMakeTmp/CheckSymbolExists.c:8:19:
 error: use of undeclared identifier '_iconv_close'; did you mean 'iconv_close'?
  return ((int*)(&_iconv_close))[argc];
                  ^~~~~~~~~~~~
                  iconv_close
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/iconv.h:78:36:
 note: 'iconv_close' declared here
extern __LIBICONV_DLL_EXPORTED int iconv_close (iconv_t _cd);
                                   ^
1 error generated.
make[1]: *** [CMakeFiles/cmTC_825af.dir/CheckSymbolExists.c.o] Error 1
make: *** [cmTC_825af/fast] Error 2


File 
/Users/nsands/Documents/Development/3rdParty/GDAL3/gdal-3.5.0/build/CMakeFiles/CMakeTmp/CheckSymbolExists.c:
/* */
#include <iconv.h>

int main(int argc, char** argv)
{
  (void)argv;
#ifndef _iconv_close
  return ((int*)(&_iconv_close))[argc];
#else
  (void)argc;
  return 0;
#endif
}
==========

Now if I try the following:

export LDFLAGS=-L/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib
export CFLAGS="-isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"
export CCFLAGS="-isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"
export CXXFLAGS="-isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"
export CPPFLAGS="-isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"
cd gdal-{VERSION}
rm -r build
mkdir build
cd build
cmake -DSQLITE3_INCLUDE_DIR=~/build/include 
-DSQLITE3_LIBRARY=~/build/lib/libsqlite3.a ..

Then the -lsystem and -lc++ errors disappear, but the iconv errors are still 
there.

I’m clearly doing something quite wrong, but I’m just a hobbyist and cannot 
figure it out any further than this.

Thanks for bearing with me if you’ve managed to read this far.  I’d be grateful 
for some assistance to get this to build using cmake.

Cheers,
Nik.

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--
http://www.spatialys.com
My software is free, but my time generally not.



========================================================
NIK SANDS
Line Tamer | Time Traveller | Space Cadet

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