# Build Error when using -DCMAKE\_CXX\_FLAGS\_DEBUG="/MTd" flag in C++
**URL:** https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748
**Category:** Uncategorized
**Tags:** cmake
**Created:** [January 8, 2021, 5:37am UTC](https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748 "2021-01-08T05:37:17Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@viki](https://discourse.itk.org/u/viki)
#### Post date: [January 8, 2021, 5:37am UTC](https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748/1 "2021-01-08T05:37:17Z")
Hi,
I am facing build error, when using -DCMAKE\_CXX\_FLAGS\_DEBUG="/MTd" .
**cmake\_code:**
cmake …\ITK -DCMAKE\_CXX\_FLAGS\_RELEASE="/MT" -DCMAKE\_CXX\_FLAGS\_DEBUG="/MTd" -DITK\_SKIP\_PATH\_LENGTH\_CHECKS=ON -DModule\_ITKIOGDCM=OFF -DModule\_ITKGDCMIO=OFF -DITK\_USE\_SYSTEM\_JPEG=OFF -DITK\_USE\_SYSTEM\_PNG=OFF -DBUILD\_TESTING=OFF -DBUILD\_EXAMPLES=OFF -G “Visual Studio 15 2017 Win64”
After Building . i have added following comment:
cmake.exe --build . --config Debug --target ALL\_BUILD
**Error:**
“E:\test1\New folder\1\build\_MTD\ALL\_BUILD.vcxproj” (default target) (1) -\>
“E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\ITKTestKernel-all.vcxproj” (default target) (238) -\>
“E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj” (default target) (239) -\>
(Link target) -\>
ITKniftiio-5.1.lib(nifti1\_io.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\1\bu
ild\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_win32.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\1\build
\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder
\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKgiftiio-5.1.lib(gifti\_io.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\1\bui
ld\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKgiftiio-5.1.lib(gifti\_xml.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\1\bu
ild\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKEXPAT-5.1.lib(xmlparse.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\1\build
\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_aligned\_free referenced in
function gdcmopenjp2opj\_aligned\_free [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj
]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_aligned\_malloc referenced i
n function opj\_aligned\_alloc\_n [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_aligned\_realloc referenced
in function opj\_aligned\_realloc\_n [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(pngrtran.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\1\build\_MTD
\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_aux.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\1\build\_MTD
\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(j2k.obj) : error LNK2001: unresolved external symbol \__imp\_floor [E:\test1\New folder\1\build_
MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(dwt.obj) : error LNK2001: unresolved external symbol \__imp\_floor [E:\test1\New folder\1\build_
MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(t1.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\1\build\_M
TD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(png.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\1\build\_MTD\Modu
les\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKniftiio-5.1.lib(nifti1\_io.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_fdclass referenced in function n
ifti\_read\_buffer [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKznz-5.1.lib(znzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_feof referenced in function znzeof [E:\t
est1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKznz-5.1.lib(znzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_fgets referenced in function znzgets [E:
\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKznz-5.1.lib(znzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_rewind referenced in function znzrewind
[E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKNrrdIO-5.1.lib(read.obj) : error LNK2019: unresolved external symbol \_\_imp\_fileno referenced in function itk\_\_nrrd
Calloc [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKNrrdIO-5.1.lib(encodingRaw.obj) : error LNK2001: unresolved external symbol \_\_imp\_fileno [E:\test1\New folder\1\bu
ild\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(fileno.obi) : error LNK2001: unresolved external symbol \_\_imp\_fileno [E:\test1\New folder\1\build\_MTD\Mo
dules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKNrrdIO-5.1.lib(gzio.obj) : error LNK2019: unresolved external symbol \_\_imp\_ferror referenced in function itk\_\_nrrd
GzRead [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(pngwrite.obj) : error LNK2001: unresolved external symbol \_\_imp\_ferror [E:\test1\New folder\1\build\_MT
D\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkjpeg-5.1.lib(jdatadst.obj) : error LNK2001: unresolved external symbol \_\_imp\_ferror [E:\test1\New folder\1\build\_M
TD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(png.obj) : error LNK2019: unresolved external symbol \_\_imp\_modf referenced in function itk\_png\_ascii\_f
rom\_fp [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_dirinfo.obj) : error LNK2019: unresolved external symbol \_\_imp\_bsearch referenced in function itk
\_TIFFFindField [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_luv.obj) : error LNK2019: unresolved external symbol \_\_imp\_rand referenced in function itk\_LogL16
fromY [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzread.obj) : error LNK2019: unresolved external symbol \_\_imp\_close referenced in function itkzlib\_gz
close\_r [E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzwrite.obj) : error LNK2001: unresolved external symbol \_\_imp\_close [E:\test1\New folder\1\build\_MTD
\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(close.obi) : error LNK2001: unresolved external symbol \_\_imp\_close [E:\test1\New folder\1\build\_MTD\Modu
les\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzread.obj) : error LNK2019: unresolved external symbol \_\_imp\_read referenced in function gz\_load [E:
\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(read.obi) : error LNK2001: unresolved external symbol \_\_imp\_read [E:\test1\New folder\1\build\_MTD\Module
s\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzwrite.obj) : error LNK2019: unresolved external symbol \_\_imp\_write referenced in function gz\_comp [
E:\test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(write.obi) : error LNK2001: unresolved external symbol \_\_imp\_write [E:\test1\New folder\1\build\_MTD\Modu
les\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_open referenced in function gz\_open [E:
test1\New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(open.obi) : error LNK2001: unresolved external symbol \_\_imp\_open [E:\test1\New folder\1\build\_MTD\Module
s\Core\TestKernel\src\itkTestDriver.vcxproj]
E:\test1\New folder\1\build\_MTD\bin\Debug\itkTestDriver.exe : fatal error LNK1120: 18 unresolved externals [E:\test1
New folder\1\build\_MTD\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
```
337 Warning(s)
38 Error(s)
```
how to solve this error, in my cmake any flags are missed ? if i missed any flag ,please tell me what flag i missed.
Thanks!
---
### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [January 8, 2021, 3:23pm UTC](https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748/2 "2021-01-08T15:23:55Z")
You are seriously modifying default Visual Studio’s flags. For release you are requesting static multi-threaded standard run-time library. For debug, you are requesting dynamic debug multi-threaded standard run-time library. The usual way is both are either static or dynamic (DLL). What are you trying to accomplish?
Maybe start from defaults, and then modify them. Get the defaults by running CMake or CMake-GUI without any custom options. For example, default `CMAKE_CXX_FLAGS_DEBUG` = `/MDd /Zi /Ob0 /Od /RTC1`.
---
### Author:  [@viki](https://discourse.itk.org/u/viki)
#### Post date: [January 9, 2021, 8:11am UTC](https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748/3 "2021-01-09T08:11:51Z")
Hi dzenanz !
Thanks For your Response.
For release you are requesting static multi-threaded standard run-time library.-yes correct.
For debug, you are requesting dynamic debug multi-threaded standard run-time library.-Debug also i am requesting MTd(static Multi threaded debug standard run-time library) .not requesting MDd(Multi threaded Debug Dll)
I am trying to build both Debug and release as static multi-threaded runtime Library.
---
### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [January 9, 2021, 5:17pm UTC](https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748/4 "2021-01-09T17:17:35Z")
> [@viki](#):
>
> not requesting MDd(Multi threaded Debug Dll)
You are right, I did not pay enough attention.
You also need to use the same flags for `CMAKE_C_FLAGS` in addition to `CMAKE_CXX_FLAGS`. I still think starting from CMake defaults and modifying what you want is better than building flags from scratch.
---
### Author:  [@viki](https://discourse.itk.org/u/viki)
#### Post date: [January 12, 2021, 6:16am UTC](https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748/5 "2021-01-12T06:16:55Z")
Hi dzenanz !
i used this flags `CMAKE_C_FLAGS``CMAKE_CXX_FLAGS` .still facing same error only.
**CMAKE:**
`cmake ..\ITK -DCMAKE_CXX_FLAGS_RELEASE="/MT" -DCMAKE_C_FLAGS="/MTd" -DCMAKE_CXX_FLAGS_DEBUG="/MTd" -DITK_SKIP_PATH_LENGTH_CHECKS=ON -DModule_ITKIOGDCM=OFF -DModule_ITKGDCMIO=OFF -DITK_USE_SYSTEM_JPEG=OFF -DITK_USE_SYSTEM_PNG=OFF -DBUILD_TESTING=OFF -DBUILD_EXAMPLES=OFF -G "Visual Studio 15 2017 Win64"`
ERROR
“E:\test1\New folder\2\build1\ALL\_BUILD.vcxproj” (default target) (1) -\>
“E:\test1\New folder\2\build1\Modules\Core\TestKernel\ITKTestKernel-all.vcxproj” (default target) (238) -\>
“E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj” (default target) (239) -\>
(Link target) -\>
ITKniftiio-5.1.lib(nifti1\_io.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\2\bu
ild1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_win32.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\2\build
1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder
\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKgiftiio-5.1.lib(gifti\_io.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\2\bui
ld1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKgiftiio-5.1.lib(gifti\_xml.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\2\bu
ild1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKEXPAT-5.1.lib(xmlparse.obj) : error LNK2001: unresolved external symbol \_\_imp\_realloc [E:\test1\New folder\2\build
1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_aligned\_free referenced in
function gdcmopenjp2opj\_aligned\_free [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_aligned\_malloc referenced i
n function opj\_aligned\_alloc\_n [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(opj\_malloc.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_aligned\_realloc referenced
in function opj\_aligned\_realloc\_n [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(pngrtran.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\2\build1\Mo
dules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_aux.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\2\build1\Mo
dules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(j2k.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\2\build1
\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(dwt.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\2\build1
\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkgdcmopenjp2-5.1.lib(t1.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\2\build1
Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(png.obj) : error LNK2001: unresolved external symbol \_\_imp\_floor [E:\test1\New folder\2\build1\Modules
\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKniftiio-5.1.lib(nifti1\_io.obj) : error LNK2019: unresolved external symbol \_\_imp\_\_fdclass referenced in function n
ifti\_read\_buffer [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKznz-5.1.lib(znzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_feof referenced in function znzeof [E:\t
est1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKznz-5.1.lib(znzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_fgets referenced in function znzgets [E:
\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKznz-5.1.lib(znzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_rewind referenced in function znzrewind
[E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKNrrdIO-5.1.lib(read.obj) : error LNK2019: unresolved external symbol \_\_imp\_fileno referenced in function itk\_\_nrrd
Calloc [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKNrrdIO-5.1.lib(encodingRaw.obj) : error LNK2001: unresolved external symbol \_\_imp\_fileno [E:\test1\New folder\2\bu
ild1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(fileno.obi) : error LNK2001: unresolved external symbol \_\_imp\_fileno [E:\test1\New folder\2\build1\Modul
es\Core\TestKernel\src\itkTestDriver.vcxproj]
ITKNrrdIO-5.1.lib(gzio.obj) : error LNK2019: unresolved external symbol \_\_imp\_ferror referenced in function itk\_\_nrrd
GzRead [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(pngwrite.obj) : error LNK2001: unresolved external symbol \_\_imp\_ferror [E:\test1\New folder\2\build1\M
odules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkjpeg-5.1.lib(jdatadst.obj) : error LNK2001: unresolved external symbol \_\_imp\_ferror [E:\test1\New folder\2\build1
Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkpng-5.1.lib(png.obj) : error LNK2019: unresolved external symbol \_\_imp\_modf referenced in function itk\_png\_ascii\_f
rom\_fp [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_dirinfo.obj) : error LNK2019: unresolved external symbol \_\_imp\_bsearch referenced in function itk
\_TIFFFindField [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itktiff-5.1.lib(tif\_luv.obj) : error LNK2019: unresolved external symbol \_\_imp\_rand referenced in function itk\_LogL16
fromY [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzread.obj) : error LNK2019: unresolved external symbol \_\_imp\_close referenced in function itkzlib\_gz
close\_r [E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzwrite.obj) : error LNK2001: unresolved external symbol \_\_imp\_close [E:\test1\New folder\2\build1\Mo
dules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(close.obi) : error LNK2001: unresolved external symbol \_\_imp\_close [E:\test1\New folder\2\build1\Modules
\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzread.obj) : error LNK2019: unresolved external symbol \_\_imp\_read referenced in function gz\_load [E:
\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(read.obi) : error LNK2001: unresolved external symbol \_\_imp\_read [E:\test1\New folder\2\build1\Modules\C
ore\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzwrite.obj) : error LNK2019: unresolved external symbol \_\_imp\_write referenced in function gz\_comp [
E:\test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(write.obi) : error LNK2001: unresolved external symbol \_\_imp\_write [E:\test1\New folder\2\build1\Modules
\Core\TestKernel\src\itkTestDriver.vcxproj]
itkzlib-5.1.lib(gzlib.obj) : error LNK2019: unresolved external symbol \_\_imp\_open referenced in function gz\_open [E:
test1\New folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
OLDNAMES.lib(open.obi) : error LNK2001: unresolved external symbol \_\_imp\_open [E:\test1\New folder\2\build1\Modules\C
ore\TestKernel\src\itkTestDriver.vcxproj]
E:\test1\New folder\2\build1\bin\Debug\itkTestDriver.exe : fatal error LNK1120: 18 unresolved externals [E:\test1\New
folder\2\build1\Modules\Core\TestKernel\src\itkTestDriver.vcxproj]
```
337 Warning(s)
38 Error(s)
```
---
### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [January 12, 2021, 5:39pm UTC](https://discourse.itk.org/t/build-error-when-using-dcmake-cxx-flags-debug-mtd-flag-in-c/3748/6 "2021-01-12T17:39:15Z")
`CMAKE_C_FLAGS_DEBUG` take priority over `CMAKE_C_FLAGS`. If you also set `CMAKE_C_FLAGS_DEBUG` to `/MTd` the build succeeds. Your release config flags are even more obviously unsynchronized. Take a look at the configuration in CMake-GUI to see all the options. Here is a screenshot of configuration which built fine in Debug mode:
