Windows MSVC 2019 EXV_ICONV_CONST undefined

[tester0077]

Compiling the code form a newly cloned version from Github, (expected/intended to be 0.27-maintenance) under MSVC 2019 for a 32-bit version of Exiv2:
In convert.cpp the line
EXV_ICONV_CONST char* inptr = const_cast<char*>(str.c_str());

the line shown, causes the error:
1>convert.cpp
1>D:\pkg\C++\MSVC2019\exiv2Git\exiv2\src\convert.cpp(1527,25): error C2664: 'size_t libiconv(libiconv_t,const char **,size_t *,char **,size_t *)': cannot convert argument 2 from 'char **' to 'const char **'
1>D:\pkg\C++\MSVC2019\exiv2Git\exiv2\src\convert.cpp(1528,31): message : Conversion loses qualifiers
1>C:\gnuwin32\include\iconv.h(92,37): message : see declaration of 'libiconv'

This error causes most of the other sub-projects to also fail.
Replacing EXV_ICONV_CONST with a plain 'const' allow this file to compile cleanly as well as all of the rest.

The sln file was created following the instructions for Windows MSVC compile https://github.com/Exiv2/exiv2/blob/master/README-CONAN.md

At this stage I have no idea about the version of libiconv, but the entire setup was presumably vetted by the conan install & update process.

Searching for the string "EXV_ICONV_CONST" does not show any instance except the line giving the error, implying that for the current setup it is not defined

Desktop (please complete the following information):

• OS: Windows 10, 64-bit
• Compiler & Version MSVC 2019
• Compilation mode and/or compiler flags

[clanmills]

I documented my profile and build procedure in #1251. When I ran the command:

C:\Users\rmills\gnu\github\exiv2\0.27-maintenance\arnold>cmake .. -G "Visual Studio 16 2019"
-- Selecting Windows SDK version 10.0.19041.0 to target Windows 10.0.18362.
-- The CXX compiler identification is MSVC 19.26.28806.0
-- The C compiler identification is MSVC 19.26.28806.0
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.26.28801/bin/Hostx64/x64/cl.exe
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.26.28801/bin/Hostx64/x64/cl.exe -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.26.28801/bin/Hostx64/x64/cl.exe
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.26.28801/bin/Hostx64/x64/cl.exe -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Conan: Using cmake targets configuration
-- Library zlib found C:/Users/rmills/.conan/data/zlib/1.2.11/conan/stable/package/a79a557254fabcb77849dd623fed97c9c5ab7651/lib/zlib.lib
-- Library gmock_main found C:/Users/rmills/.conan/data/gtest/1.8.1/bincrafters/stable/package/146430f32dcfadc1d6e788655671192747f9b80f/lib/gmock_main.lib
-- Library gmock found C:/Users/rmills/.conan/data/gtest/1.8.1/bincrafters/stable/package/146430f32dcfadc1d6e788655671192747f9b80f/lib/gmock.lib
-- Library gtest found C:/Users/rmills/.conan/data/gtest/1.8.1/bincrafters/stable/package/146430f32dcfadc1d6e788655671192747f9b80f/lib/gtest.lib
-- Library expat found C:/Users/rmills/.conan/data/Expat/2.2.6/pix4d/stable/package/015f2e164166e1813636fed4e71853aa01bc65a2/lib/expat.lib
-- Conan: Adjusting language standard
-- Current conanbuildinfo.cmake directory: C:/Users/rmills/gnu/github/exiv2/0.27-maintenance/arnold
-- Looking for pthread.h
-- Looking for pthread.h - not found
-- Found Threads: TRUE
-- Found ZLIB: C:/Users/rmills/.conan/data/zlib/1.2.11/conan/stable/package/a79a557254fabcb77849dd623fed97c9c5ab7651/lib/zlib.lib (found version "1.2.11")
-- Found EXPAT: C:/Users/rmills/.conan/data/Expat/2.2.6/pix4d/stable/package/015f2e164166e1813636fed4e71853aa01bc65a2/lib/expat.lib (found version "2.2.6")
-- Could NOT find Iconv (missing: Iconv_LIBRARY)    <---- DID NOT FIND ICONV
-- Looking for gmtime_r
-- Looking for gmtime_r - not found
-- Looking for mmap
-- Looking for mmap - not found
-- Looking for munmap
-- Looking for munmap - not found
-- Looking for strerror_r
-- Looking for strerror_r - not found
-- Performing Test EXV_STRERROR_R_CHAR_P
-- Performing Test EXV_STRERROR_R_CHAR_P - Failed
-- Looking for C++ include memory.h
-- Looking for C++ include memory.h - found
-- Looking for C++ include process.h
-- Looking for C++ include process.h - found
-- Looking for C++ include stdbool.h
-- Looking for C++ include stdbool.h - found
-- Looking for C++ include stdint.h
-- Looking for C++ include stdint.h - found
-- Looking for C++ include strings.h
-- Looking for C++ include strings.h - not found
-- Looking for C++ include sys/stat.h
-- Looking for C++ include sys/stat.h - found
-- Looking for C++ include sys/types.h
-- Looking for C++ include sys/types.h - found
-- Looking for C++ include inttypes.h
-- Looking for C++ include inttypes.h - found
-- Looking for C++ include unistd.h
-- Looking for C++ include unistd.h - not found
-- Looking for C++ include sys/mman.h
-- Looking for C++ include sys/mman.h - not found
-- Performing Test COMPILER_HAS_DEPRECATED_ATTR
-- Performing Test COMPILER_HAS_DEPRECATED_ATTR - Failed
-- Performing Test COMPILER_HAS_DEPRECATED
-- Performing Test COMPILER_HAS_DEPRECATED - Success
-- Install prefix:    C:/Program Files (x86)/exiv2
-- ------------------------------------------------------------------
-- CMake Generator:   Visual Studio 16 2019
-- CMAKE_BUILD_TYPE:
-- Compiler info: MSVC (C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.26.28801/bin/Hostx64/x64/cl.exe) ; version: 19.26.28806.0
-- CMAKE_CXX_STANDARD:
--  --- Compiler flags ---
-- General:           /DWIN32 /D_WINDOWS /W3 /GR /EHsc
         /MP
         /Zc:__cplusplus
-- Extra:
-- Debug:             /MDd /Zi /Ob0 /Od /RTC1
-- Release:           /MD /O2  /DNDEBUG
-- RelWithDebInfo:    /MD /Zi /O2  /DNDEBUG
-- MinSizeRel:        /MD /O1  /DNDEBUG
--  --- Linker flags ---
-- General:           /machine:x64
-- Debug:             /debug /INCREMENTAL
-- Release:           /INCREMENTAL:NO
-- RelWithDebInfo:    /debug /INCREMENTAL
-- MinSizeRel:        /INCREMENTAL:NO
--
-- Compiler Options
-- Warnings as errors:                 NO
-- Use extra compiler warning flags:   NO
--
-- ------------------------------------------------------------------
-- Building shared library:            YES
-- Building PNG support:               YES
-- XMP metadata support:               YES
-- Native language support:            NO
-- Conversion of Windows XP tags:      YES
-- Nikon lens database:                YES
-- Building video support:             NO
-- Building webready support:          NO
-- Dynamic runtime override:           YES
-- Unicode paths (wstring):            NO
-- Building exiv2 command:             YES
-- Building samples:                   YES
-- Building PO files:                  NO
-- Building unit tests:                NO
-- Building doc:                       NO
-- Building with coverage flags:       NO
-- Using ccache:                       NO
-- ------------------------------------------------------------------
--  WARNING: Deprecated features: EPS, Video, Ssh
-- ------------------------------------------------------------------
-- Configuring done
-- Generating done
-- Build files have been written to: C:/Users/rmills/gnu/github/exiv2/0.27-maintenance/arnold

C:\Users\rmills\gnu\github\exiv2\0.27-maintenance\arnold>

CMake generate the sln and several vcprojx files. He also generates this file:

C:\Users\rmills\gnu\github\exiv2\0.27-maintenance\arnold>type exv_conf.h
// File generated by cmake from cmake/config.h.cmake.

#ifndef _EXV_CONF_H_
#define _EXV_CONF_H_

// Defined if you want to use libssh for SshIO.
/* #undef EXV_USE_SSH */

// Define to 1 if you want to use libcurl in httpIO.
/* #undef EXV_USE_CURL */

// Define if you require webready support.
/* #undef EXV_ENABLE_WEBREADY */

// Define if you have the <libintl.h> header file.
/* #undef EXV_HAVE_LIBINTL_H */

// Define if you want translation of program messages to the user's native language
/* #undef EXV_ENABLE_NLS */

// Define if you want video support.
/* #undef EXV_ENABLE_VIDEO */

// Define if you have the strerror_r function.
/* #undef EXV_HAVE_STRERROR_R */

// Define if the strerror_r function returns char*.
/* #undef EXV_STRERROR_R_CHAR_P */

// Define to enable the Windows unicode path support.
/* #undef EXV_UNICODE_PATH */

/* Define to `const' or to empty, depending on the second argument of `iconv'. */
/* #undef ICONV_ACCEPTS_CONST_INPUT */
#if defined(ICONV_ACCEPTS_CONST_INPUT) || defined(__NetBSD__)
#define EXV_ICONV_CONST const
#else
#define EXV_ICONV_CONST     <---- CORRECT EXV_ICONV_CONST is nothing!
#endif

// Define if you have the <regex.h> header file.
/* #undef EXV_HAVE_REGEX_H */

// Define if have the <memory.h> header file.
#define EXV_HAVE_MEMORY_H

// Define if stdbool.h conforms to C99.
#define EXV_HAVE_STDBOOL_H

// Define if you have the <stdint.h> header file.
#define EXV_HAVE_STDINT_H

// Define if you have the <strings.h> header file.
/* #undef EXV_HAVE_STRINGS_H */

// Define if you have the mmap function.
/* #undef EXV_HAVE_MMAP */

// Define if you have the munmap function.
/* #undef EXV_HAVE_MUNMAP */

// Define if you have <sys/stat.h> header file.
#define EXV_HAVE_SYS_STAT_H

// Define if you have  the <sys/types.h> header file.
#define EXV_HAVE_SYS_TYPES_H

/* Define if you have the <unistd.h> header file. */
/* #undef EXV_HAVE_UNISTD_H */

// Define if you have the <sys/mman.h> header file.
/* #undef EXV_HAVE_SYS_MMAN_H */

// Define if you have are using the zlib library.
#define EXV_HAVE_LIBZ

// Define if you have the <process.h> header file.
#define EXV_HAVE_PROCESS_H

/* Define if you have (Exiv2/xmpsdk) Adobe XMP Toolkit. */
#define EXV_HAVE_XMP_TOOLKIT

/* Define to the full name of this package. */
#define EXV_PACKAGE_NAME "exiv2"

/* Define to the full name and version of this package. */
#define EXV_PACKAGE_STRING "exiv2 0.27.3.20"

/* Define to the version of this package. */
#define EXV_PACKAGE_VERSION "0.27.3.20"

#define EXIV2_MAJOR_VERSION (0)
#define EXIV2_MINOR_VERSION (27)
#define EXIV2_PATCH_VERSION (3)
#define EXIV2_TWEAK_VERSION (20)

// Definition to enable translation of Nikon lens names.
#define EXV_HAVE_LENSDATA

// Define if you have the iconv function.
/* #undef EXV_HAVE_ICONV */                   <---- CORRECT WE DON'T HAVE ICONV

// Definition to enable conversion of UCS2 encoded Windows tags to UTF-8.
#define EXV_HAVE_PRINTUCS2

#endif /* !_EXV_CONF_H_ */

C:\Users\rmills\gnu\github\exiv2\0.27-maintenance\arnold>

Can you run the cmake command and let me see both the output from CMake and the file exv_conf.h which is generated.

I suspect that you are picking up a "rogue" version of exv_conf.h and not the one generated by CMake. There is a compiler setting in Visual Studio "Show Includes" which echos the path of include files used by the compiler.

I also suspect that you are detecting iconv on your platform and we can confirm that with the output from the cmake .. -G do-dah command.

I don't know anything very much about ICONV. It was added to Exiv2 before I joined the project in 2008 and hasn't caused significant pain. I believe it's purpose is to perform character conversion for comments and used by the UserComment, GPSInfo.GPSProcessingMethod and GPSInfo.GPSAreaInformation I updated the Exiv2 man page in 0.27.3 to explain how to use UNICODE and other character sets in those tags.

[tester0077]

Hi Robbin,
thank you for the quick response, but this issue only concerns a macro which seems undefined

Compiling the code form a newly cloned version from Github, (expected/intended to be 0.27-maintenance) under MSVC 2019 for a 32-bit version of Exiv2:
In convert.cpp the line
EXV_ICONV_CONST char* inptr = const_cast<char*>(str.c_str());

though it may well be related to my trying for a 32-bit compile.
I'll respond to the other issue related to #976 later today, once I have had a better chance at sorting out the details and I will try add my conan profile and commands at that time

[clanmills]

Only one b in Robin (some would say there are lots of bees in Robin)

I would like to see:

1. output of the command cmake .. -G doo-dah when you create your solution file
2. the generated file exv_conf.h

If they seem to correct (mine are above), then you need to switch on the compilers "Show include files" input file and find out which exv_conf.h is being used.

I don't know how you can get a 32 bit build from Visual Studio 2019 Community Edition. For sure, it doesn't offer it to me.

Robin

[tester0077]

My sincere apologies for misspelling your name, Robin.
My only excuse is that it was ~ 4:00 AM when I could not sleep.

buildOutput.txt

exv_conf.zip

As for getting 32-bit compile from MSCVC community edition, I have done so for ages - moving up over the years from MSVC 2005 and have never had any problems with that. In fact, the recent versions - after about 2010, make it possible to use tool chains from earlier compilers, which means I probably could compile using MSVC 2010 libraries for XP
Arnold

[clanmills]

Solved. CMake is picking up something suspicious.

-- Found Iconv: C:/gnuwin32/lib/libiconv.lib
-- ICONV_INCLUDE_DIR : C:/gnuwin32/include
-- ICONV_LIBRARIES : C:/gnuwin32/lib/libiconv.lib

The quick fix is to modify the file cmake/FindIconv.cmake to never attempt to find Iconv when building with Visual Studio:

#if ( NOT MSVC )
... all of the existing code....
#endif

There's very little in README.md about libiconv. The final "tweak" in Exiv2 v0.27.3 was to add section 2.18 Static and Shared Libraries which was added in response to a user issue concerning linking libiconv. I wrote the documentation without understanding the issue which was handled by @piponazo

I looked at an article today on CodeProject about building libiConv on Windows. https://www.codeproject.com/Articles/302012/How-to-Build-libiconv-with-Microsoft-Visual-Studio I'm going to read the article in CodeProject and then decide what to do about this.

I see you are building from master. I haven't submitted anything to master for about 2 years. When I do something about this, it'll go into the 0.27-maintenance branch. Will changes get ported to 'master'? I don't know.

[tester0077]

It was my intention to build from 0.27.3-maintenance, but with my current level of git & Github skills I might be off on that, and evidently am.

Which would be the recommended link to work from?

FWIW, the 0.27.2 link on https://github.com/Exiv2/exiv2/projects is dead.

In working with this issue, I had noticed that conan seemed to pick my 32-bit libiconv in c:\gnuwin32\bin.
It struck me as odd, but not being familiar with 32/64-bit interoperability I don't know if that is kosher or not.
In one or other of my projects I believe I had to build libiconv in the past, and in fact, the very project I am working on right now includes a copy - though I have no idea which version, nor do I recall where it came from, but it keeps the compiler & linker happy.

[clanmills]

Thanks for letting me know about the broken link. I've fixed that and added links to the 0.27.3 release tags.

I think you should work on 0.27-maintenance for now because I'm active in that branch.

Lots of good work has been done in the past on 0.28 on 'master'. Progress this year has been glacial and I wonder if 0.28 will ever be finished. I'm totally focused on my book and say "It'll be finished in 2020". I'm hoping it might get finished by the end of August. I've offered to release 'master' as 0.28 and had no response.

Set up a clone of 0.27-maintenance and work there:

$ mkdir c:\Users\yourusername\gnu\github\exiv2
$ git clone https://github.com/exiv2/exiv2 --branch 0.27-maintenance 0.27-maintenance --depth 1
$ cd 0.27-maintenance
$ git fetch --unshallow
$ mkdir build
$ cd build
$ conan install .. --profile aaaaaaa --build missing
$ cmake .. -G do-dah -DEXIV2_ENABLE_DYNAMIC_RUNTIME=Off -DBUILD_SHARED_LIBS=Off
$ cmake --build . --config Release

In README.md for Exiv2 v0.27.3, I have documented my batch file cmd64.bat which I use to set up my cmd shell for building. It uses a "stripped" down PATH to protect the build environment from finding Cygwin64 or MinGW/msys2 libraries. You may find that batch file also "hides" C:/gnuwin32 from CMake for you.

I read the article on Code Project. I will add the if (NOT MSVC)...endif() to cmake/FindIconv.cmake and say something about libiconv in README.md. like this:

In general libiconv is a GNU library and we do not recommend building Exiv2 on Visual Studio to use libiconv. There is an article here about building libiconv with Visual Studio. If you are successful in building the library, you will have to remove the "guard" in cmake/FindIconv.cmake which ensures that Visual Studio never finds libiconv.

Right. Saturday Night. I seldom watch TV, however there's a program this evening that interests me and Alison: https://www.bbc.co.uk/programmes/m000l3vn

[tester0077]

following your instructions, I cloned a new repository , as follows:

CD D:\pkg\C++\MSVC2019\exiv2Git\
git clone https://github.com/exiv2/exiv2 --branch 0.27-maintenance 0.27-maintenance --depth 1
cd 0.27-maintenance
git fetch --unshallow
mkdir build32deb
mkdir build32rel
cd build32deb
conan install .. --build missing --profile msvc2019Debug32Static
cmake .. -G "Visual Studio 16 2019" -A Win32 -DEXIV2_ENABLE_DYNAMIC_RUNTIME=Off -DBUILD_SHARED_LIBS=Off
cmake --build . --config Debug

When I compare the changes between my old version and the new 0.27-maint code using KDiff3, I find loads of changes from what I had.
The curious thing is that when I let CMake compile the works, I get the following output:

 exiv2-xmp.vcxproj -> D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\lib\Debug\exiv2-xmp.lib
  Building Custom Rule D:/pkg/C++/MSVC2019/exiv2Git/0.27-maintenance/src/CMakeLists.txt
  basicio.cpp
  bigtiffimage.cpp
  bmpimage.cpp
  convert.cpp
  cr2image.cpp
  crwimage.cpp
  datasets.cpp
  easyaccess.cpp
D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\src\basicio.cpp(1304,41): warning C4018: '>': signed/unsigned mismatch [D
:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\src\exiv2lib.vcxproj]
**D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\src\convert.cpp(1548,25): error C2664: 'size_t libiconv(libiconv_t,const
char **,size_t *,char **,size_t *)': cannot convert argument 2 from 'char **' to 'const char **' [D:\pkg\C++\MSVC2019\e
xiv2Git\0.27-maintenance\build32deb\src\exiv2lib.vcxproj]
D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\src\convert.cpp(1549,31): message : Conversion loses qualifiers [D:\pkg\C
++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\src\exiv2lib.vcxproj]**
C:\gnuwin32\include\iconv.h(92,37): message : see declaration of 'libiconv' (compiling source file D:\pkg\C++\MSVC2019\
exiv2Git\0.27-maintenance\src\convert.cpp) [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\src\exiv2lib.vcxpr
oj]
  epsimage.cpp

if I replace the line in convert.cpp # 1542
EXV_ICONV_CONST char* inptr = const_cast<char*>(str.c_str());
with
const char* inptr = const_cast<char*>(str.c_str());

exiv2lib builds without complaint, but I get a whole lot of warning and some other errors, which did not show up before:

D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb>cmake --build . --config Debug
Microsoft (R) Build Engine version 16.6.0+5ff7b0c9e for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

  Checking Build System
  Building Custom Rule D:/pkg/C++/MSVC2019/exiv2Git/0.27-maintenance/src/CMakeLists.txt
  canonmn_int.cpp
  casiomn_int.cpp
  cr2header_int.cpp
  crwimage_int.cpp
  fujimn_int.cpp
  helper_functions.cpp
  image_int.cpp
  makernote_int.cpp
  minoltamn_int.cpp
  nikonmn_int.cpp
  olympusmn_int.cpp
  orfimage_int.cpp
  panasonicmn_int.cpp
  pentaxmn_int.cpp
  rw2image_int.cpp
  samsungmn_int.cpp
  sigmamn_int.cpp
  sonymn_int.cpp
  tags_int.cpp
  tiffcomposite_int.cpp
  tiffimage_int.cpp
  tiffvisitor_int.cpp
  pngchunk_int.cpp
  exiv2lib_int.vcxproj -> D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\src\exiv2lib_int.dir\Debug\exiv2lib_
  int.lib
  Building Custom Rule D:/pkg/C++/MSVC2019/exiv2Git/0.27-maintenance/xmpsdk/CMakeLists.txt
  ExpatAdapter.cpp
  MD5.cpp
  ParseRDF.cpp
  UnicodeConversions.cpp
  WXMPIterator.cpp
  WXMPMeta.cpp
  WXMPUtils.cpp
  XML_Node.cpp
  XMPCore_Impl.cpp
  XMPIterator.cpp
  XMPMeta-GetSet.cpp
  XMPMeta-Parse.cpp
  XMPMeta-Serialize.cpp
  XMPMeta.cpp
  XMPUtils-FileInfo.cpp
  XMPUtils.cpp
  exiv2-xmp.vcxproj -> D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\lib\Debug\exiv2-xmp.lib
  Building Custom Rule D:/pkg/C++/MSVC2019/exiv2Git/0.27-maintenance/src/CMakeLists.txt
  basicio.cpp
  bigtiffimage.cpp
  bmpimage.cpp
  convert.cpp
  cr2image.cpp
  crwimage.cpp
  datasets.cpp
  easyaccess.cpp
D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\src\basicio.cpp(1304,41): warning C4018: '>': signed/unsigned mismatch [D
:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\src\exiv2lib.vcxproj]
  epsimage.cpp
  error.cpp
  exif.cpp
  futils.cpp
  gifimage.cpp
  http.cpp
  image.cpp
  ini.cpp
  iptc.cpp
  jp2image.cpp
  jpgimage.cpp
  metadatum.cpp
  mrwimage.cpp
  orfimage.cpp
  pgfimage.cpp
  preview.cpp
  properties.cpp
  psdimage.cpp
  rafimage.cpp
  rw2image.cpp
  tags.cpp
  tgaimage.cpp
  tiffimage.cpp
  types.cpp
  value.cpp
  version.cpp
  webpimage.cpp
  xmp.cpp
  xmpsidecar.cpp
  pngimage.cpp
  exiv2lib.vcxproj -> D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\lib\Debug\exiv2.lib
  Building Custom Rule D:/pkg/C++/MSVC2019/exiv2Git/0.27-maintenance/samples/CMakeLists.txt
  addmoddel.cpp
zlib.lib(compress.obj) : warning LNK4075: ignoring '/EDITANDCONTINUE' due to '/SAFESEH' specification [D:\pkg\C++\MSVC2
019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(compress.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(compress.obj)' or at 'D:\pk
g\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++
\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(uncompr.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(uncompr.obj)' or at 'D:\pkg\
C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\M
SVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(crc32.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(crc32.obj)' or at 'D:\pkg\C++\
MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\MSVC2
019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(deflate.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(deflate.obj)' or at 'D:\pkg\
C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\M
SVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(inflate.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(inflate.obj)' or at 'D:\pkg\
C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\M
SVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(adler32.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(adler32.obj)' or at 'D:\pkg\
C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\M
SVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(zutil.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(zutil.obj)' or at 'D:\pkg\C++\
MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\MSVC2
019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(trees.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(trees.obj)' or at 'D:\pkg\C++\
MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\MSVC2
019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(inftrees.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(inftrees.obj)' or at 'D:\pk
g\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++
\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
zlib.lib(inffast.obj) : warning LNK4099: PDB 'zlibstatic.pdb' was not found with 'zlib.lib(inffast.obj)' or at 'D:\pkg\
C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\zlibstatic.pdb'; linking object as if no debug info [D:\pkg\C++\M
SVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4098: defaultlib 'MSVCRTD' conflicts with use of other libs; use /NODEFAULTLIB:library [D:\pkg\C++\MS
VC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4217: symbol '_free' defined in 'libucrtd.lib(free.obj)' is imported by 'zlib.lib(zutil.obj)' in func
tion '_zcfree' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4286: symbol '_free' defined in 'libucrtd.lib(free.obj)' is imported by 'expat.lib(xmlparse.obj)' [D:
\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4286: symbol '_free' defined in 'libucrtd.lib(free.obj)' is imported by 'expat.lib(loadlibrary.obj)'
[D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4217: symbol '_malloc' defined in 'libucrtd.lib(malloc.obj)' is imported by 'zlib.lib(zutil.obj)' in
function '_zcalloc' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4286: symbol '_malloc' defined in 'libucrtd.lib(malloc.obj)' is imported by 'expat.lib(xmlparse.obj)'
 [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4286: symbol '_malloc' defined in 'libucrtd.lib(malloc.obj)' is imported by 'expat.lib(loadlibrary.ob
j)' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4217: symbol '__wassert' defined in 'libucrtd.lib(assert.obj)' is imported by 'expat.lib(xmlparse.obj
)' in function '_XML_GetParsingStatus' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxp
roj]
LINK : warning LNK4217: symbol '___acrt_iob_func' defined in 'libucrtd.lib(_file.obj)' is imported by 'expat.lib(xmlpar
se.obj)' in function '_ENTROPY_DEBUG' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxpr
oj]
LINK : warning LNK4217: symbol '___stdio_common_vfprintf' defined in 'libucrtd.lib(output.obj)' is imported by 'expat.l
ib(xmlparse.obj)' in function '__vfprintf_l' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmodde
l.vcxproj]
LINK : warning LNK4217: symbol '_realloc' defined in 'libucrtd.lib(realloc.obj)' is imported by 'expat.lib(xmlparse.obj
)' in function '_parserCreate' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
LINK : warning LNK4217: symbol '_getenv' defined in 'libucrtd.lib(getenv.obj)' is imported by 'expat.lib(xmlparse.obj)'
 in function '_ENTROPY_DEBUG' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
expat.lib(loadlibrary.obj) : error LNK2019: unresolved external symbol __imp___mbspbrk referenced in function __tcspbrk
 [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
MSVCRTD.lib(chandler4gs.obj) : error LNK2019: unresolved external symbol __except_handler4_common referenced in functio
n __except_handler4 [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\bin\addmoddel.exe : fatal error LNK1120: 2 unresolved external
s [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
  Building Custom Rule D:/pkg/C++/MSVC2019/exiv2Git/0.27-maintenance/samples/CMakeLists.txt
  conntest.cpp
......

HTH :(

[clanmills]

Please add the code I have suggested to cmake/FindIConv.cmake and build again.

I don't think it's possible to build Exiv2 with libiconv on Visual Studio and that's what I'm going to say in README.md Since we last spoke, I've downloaded the latest version and looked at libiconv-1.16/INSTALL.windows. I wouldn't attempt to build that on Visual Studio. That's not a cross-platform library. It's a Linux thing with some hard to follow instructions to build on Windows. Exiv2, zlib and always every library was in that state in 2008.

You might encounter 32 bit oddities as we have more or less stopped building 32 bit versions now. Cygwin32 and MinGW are obsolete.

'master' and '0.27-maintenance' are diverging and this is planned and intentional. 0.27-maintenance is intended to keep Exiv2 alive while the guys finish 0.28. 0.28 is not backwards compatible.

[clanmills]

About all those linker warning and stuff. It looks to me that there is a fatal collision in zlib/expat and the c-runtime concerning _getenv()

LINK : warning LNK4217: symbol '_getenv' defined in 'libucrtd.lib(getenv.obj)' is imported by 'expat.lib(xmlparse.obj)'
 in function '_ENTROPY_DEBUG' [D:\pkg\C++\MSVC2019\exiv2Git\0.27-maintenance\build32deb\samples\addmoddel.vcxproj]
expat.lib(loadlibrary.obj) 

This didn't happen to me when I build the 64 bit configuration this morning. Can you investigating using my script cmd64.bat to "sanitise" your environment. I'll need to see the output from both the conan install .. command and the cmake .. -G doo-dah to know what libraries you are trying to use.

I personally don't like static linking and much prefer to work with DLLs. I know that static linking works. I encourage you to use dynamic linking. And I don't know why you are building a debug version of the library as applications are expect to link the release version.