eiffel c compilation failure: error LNK2001: unresolved external symbol - c

Question

I'm trying to get familiar with Eiffel language so I've installed Eiffel Studio 18 and created a Graphics application. Compilation failed with message:
Preparing C compilation using already configured msc C compiler...
ERROR: Cannot start "nmake".ERROR: Cannot start "nmake".
Documentation suggested that espawn utility may show available toolchains, however it seems to crash:
PS C:\Program Files\Eiffel Software\EiffelStudio 18.07 GPL\tools\spec\win64\bin> & "C:\Program Files\Eiffel Software\EiffelStudio 18.07 GPL\tools\spec\win64\bin\espawn.exe" -l
Eiffel Environment Command Spawn Utility - Version: 18.07
Copyright Eiffel Software 1985-2018. All Rights Reserved.
Available C/C++ compilers:
espawn: system execution failed.
Following is the set of recorded exceptions:
******************************** Thread exception *****************************
In thread Root thread 0x0 (thread id)
*******************************************************************************
-------------------------------------------------------------------------------
Class / Object Routine Nature of exception Effect
-------------------------------------------------------------------------------
APPLICATION root's creation Segmentation violation:
<000000000363C588> Operating system signal. Exit
-------------------------------------------------------------------------------
APPLICATION root's creation
<000000000363C588> Routine failure. Exit
-------------------------------------------------------------------------------
Unfortunately I couldn't find any toolchain related stuff except for that espawn util so I've tried to launch Eiffel Studio from VS development command prompt hoping that it may implicitly rely on some environment variables. This indeed helped, however compilation still fails with linker error:
Preparing C compilation using already configured msc C compiler...
big_file_C28_c.c
eoption.c
big_file_E2_c.c
big_file_C26_c.c
big_file_C27_c.c
big_file_C30_c.c
big_file_C29_c.c
big_file_C31_c.c
eref.c
epoly.c
esize.c
big_file_C25_c.c
big_file_C24_c.c
big_file_C23_c.c
big_file_C22_c.c
big_file_C21_c.c
big_file_C20_c.c
big_file_C19_c.c
eplug.c
eskelet.c
enames.c
evisib.c
big_file_C18_c.c
big_file_C17_c.c
big_file_C16_c.c
big_file_C15_c.c
big_file_C13_c.c
big_file_C14_c.c
ececil.c
big_file_C12_c.c
einit.c
eparents.c
big_file_C11_c.c
big_file_C10_c.c
big_file_C9_c.c
big_file_C8_c.c
big_file_C7_c.c
big_file_C6_c.c
big_file_C5_c.c
big_file_C4_c.c
big_file_C3_c.c
big_file_C2_c.c
big_file_C1_c.c
Скопировано файлов: 1.
emain.c
Microsoft (R) Windows (R) Resource Compiler Version 10.0.10011.16384
Copyright (C) Microsoft Corporation. All rights reserved.
Microsoft (R) Incremental Linker Version 14.16.27024.1
Copyright (C) Microsoft Corporation. All rights reserved.
-STACK:5000000 -NODEFAULTLIB:libc -STACK:5000000 -NODEFAULTLIB:libc -SUBSYSTEM:WINDOWS -OUT:my_wel_application_1.exe
e1\emain.obj
"C:\Program Files\Eiffel Software\EiffelStudio 18.07 GPL\studio\spec\win64\lib\msc\finalized.lib" "C:\Program Files\Eiffel Software\EiffelStudio 18.07 GPL\library\wel\spec\msc\win64\lib\wel.lib"
USER32.lib WS2_32.lib ADVAPI32.lib GDI32.lib SHELL32.lib MSIMG32.lib COMDLG32.lib UUID.lib OLE32.lib OLEAUT32.lib COMCTL32.lib MPR.LIB SHLWAPI.LIB WINSPOOL.LIB
my_wel_application_1.res
E2\Eobj2.lib E1\eparents.obj E1\einit.obj E1\ececil.obj E1\evisib.obj
E1\enames.obj E1\eskelet.obj E1\eplug.obj E1\esize.obj E1\epoly.obj
E1\eref.obj E1\eoption.obj C31\Cobj31.lib C30\Cobj30.lib C29\Cobj29.lib
C28\Cobj28.lib C27\Cobj27.lib C26\Cobj26.lib C25\Cobj25.lib C24\Cobj24.lib
C23\Cobj23.lib C22\Cobj22.lib C21\Cobj21.lib C20\Cobj20.lib C19\Cobj19.lib
C18\Cobj18.lib C17\Cobj17.lib C16\Cobj16.lib C15\Cobj15.lib C14\Cobj14.lib
C13\Cobj13.lib C12\Cobj12.lib C11\Cobj11.lib C10\Cobj10.lib C9\Cobj9.lib
C8\Cobj8.lib C7\Cobj7.lib C6\Cobj6.lib C5\Cobj5.lib C4\Cobj4.lib
C3\Cobj3.lib C2\Cobj2.lib C1\Cobj1.lib
finalized.lib(econsole.obj) : error LNK2001: unresolved external symbol __iob_func
finalized.lib(console.obj) : error LNK2001: unresolved external symbol __iob_func
finalized.lib(file.obj) : error LNK2001: unresolved external symbol __iob_func
finalized.lib(main.obj) : error LNK2001: unresolved external symbol __iob_func
finalized.lib(except.obj) : error LNK2001: unresolved external symbol __iob_func
finalized.lib(sig.obj) : error LNK2001: unresolved external symbol __iob_func
finalized.lib(option.obj) : error LNK2001: unresolved external symbol __iob_func
finalized.lib(main.obj) : error LNK2019: unresolved external symbol _set_output_format referenced in function eif_rtinit
finalized.lib(run_idr.obj) : error LNK2001: unresolved external symbol sprintf
finalized.lib(except.obj) : error LNK2001: unresolved external symbol sprintf
finalized.lib(out.obj) : error LNK2001: unresolved external symbol sprintf
finalized.lib(file.obj) : error LNK2001: unresolved external symbol sprintf
finalized.lib(store.obj) : error LNK2001: unresolved external symbol sprintf
finalized.lib(econsole.obj) : error LNK2019: unresolved external symbol vfprintf referenced in function print_err_msg
finalized.lib(file.obj) : error LNK2019: unresolved external symbol fscanf referenced in function rt_swallow_nl
finalized.lib(retrieve.obj) : error LNK2019: unresolved external symbol sscanf referenced in function iread_header_new
finalized.lib(run_idr.obj) : error LNK2001: unresolved external symbol sscanf
my_wel_application_1.exe : fatal error LNK1120: 6 unresolved externals
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.16.27023\bin\HostX64\x64\link.EXE"' : return code '0x460'
Stop.

Answer 1

The compilation error when running from VS development command prompt is related to the mismatch between C compiler version and used Eiffel run-time library. Setting the corresponding environment variable before launching the compilation should fix the issue:
set ISE_C_COMPILER=msc_vc140
As to the original error, for some reason, C compilation fails on some machines, because EiffelStudio cannot find VS. The issue has even become a FAQ.