WiringPi build error

[this]

@jsulm Yes, of course.
I also run rebuild.
However, the same error occurs.

[jsulm]

@this Can you show your pro file and the build log? Are you actually building for ARM?

[this]

@jsulm 

Do you need more information?

[jsulm]

@this Yes, I need the build log ("Compile Output" tab in QtCreator)

[this]

@jsulm 

I am cross compiling Linux (ubuntu) to raspberrypi.

[jsulm]

@this The lib is EABI5: "ELF 32-bit LSB shared object, ARM, EABI5". I think RPi uses EABI7 or something. From where did you get the lib?

[this]

@jsulm I'm sorry, but I do not know what lib is.
I can not understand your words.
Are you referring to qt lib?
Are you talking raspberrypi?

We have installed cross compile environment by referring to the following site.
https://medium.com/@amirmann/how-to-cross-compile-qt-for-raspberry-pi-3-on-linux-ubuntu-for-beginners-75acf2a078c

[jsulm]

@this I'm talking about libwiringPi.so
How did you install this lib? Was it part of this cross compiling environment or did you get it from somewhere else?

[this]

@jsulm I am sorry.
Installed.
The installation process is as follows:

git clone git://git.drogon.net/wiringPi
cd wiringPi/
git pull origin
./build

At first we installed wiringPi from ubuntu pc.
However, I got the error like above and installed raspberrypi in the same way.

[jsulm]

@this Sorry can you explain this: "At first we installed wiringPi from ubuntu pc.
However, I got the error like above and installed raspberrypi in the same way."

Do you mean you built it on the RaspberryPi and copied then to your Ubuntu PC?
You should build it on your Ubuntu machine, but use the cross compilation environment.

[this]

@jsulm Well ... you seem to have misunderstood.
The build is ubuntu -> raspberrypi. (Cross compile)

I have been struggling to eliminate the errors that have occurred.

I first installed wiringPi via the terminal from ubuntu pc.

However, I thought that a file not recognized error occurred and there was no file in raspberrypi.

So raspberrypi installed wiringPi through the terminal.
So I installed wiringPi related files in raspberrypi's / usr / local / lib folder.

I thought this was the cause of the error.

However, as you know, the error was not resolved and the question was raised

[jsulm]

@this I know that you're cross compiling.
"However, I thought that a file not recognized error occurred and there was no file in raspberrypi." - for cross compilation it doesn't matter whether the lib is on RaspberryPi or not as you're building on your Ubuntu machine - you need it on your Ubuntu machine.
So, on your Ubuntu machine the lib is this: /usr/local/lib/libwiringPi.so (symbolic link) and /usr/local/lib/libwiringPi.so.2.44 (lib itself), right?

[this]

This post is deleted!

[this]

@jsulm I solved the above error.
LIBS += -L/usr/local/lib-lwiringPi
I made a mistake in the spacing.
However, a new error has occurred.
Is this what I am doing wrong?
I wrote the following in .pro.
INCLUDEPATH + = / usr / local / include
LIBS += -L/usr/local/lib-lwiringPi



[this]

@this I got the above error and I deleted wiringPi and reinstalled it.
However, the following error occurs during installation.

Is this the problem that caused this error?

//////////////////////////////////////////////////////////////////////////////////////////////////////////
root@smart-HP-Z400-Workstation:~/wiringPi# ./build
wiringPi Build script

WiringPi Library
[UnInstall]
[Compile] wiringPi.c
[Compile] wiringSerial.c
[Compile] piHiPri.c
[Compile] wiringShift.c
[Compile] piThread.c
wiringSerial.c: In function ‘serialPutchar’:
wiringSerial.c:158:3: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
write (fd, &c, 1) ;
^
wiringSerial.c: In function ‘serialPuts’:
wiringSerial.c:170:3: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
write (fd, s, strlen (s)) ;
^
[Compile] softPwm.c
[Compile] wiringPiSPI.c
[Compile] wiringPiI2C.c
[Compile] softTone.c
wiringPi.c:1247:21: warning: ‘digitalRead8Dummy’ defined but not used [-Wunused-function]
static unsigned int digitalRead8Dummy (UNU struct wiringPiNodeStruct *no
^
wiringPi.c:1248:21: warning: ‘digitalWrite8Dummy’ defined but not used [-Wunused-function]
static void digitalWrite8Dummy (UNU struct wiringPiNodeStruct *no
^
wiringPi.c: In function ‘digitalRead’:
[Compile] mcp23008.c
wiringPi.c:1473:7: warning: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Wunused-result]
read (sysFds [pin], &c, 1) ;
^
wiringPi.c: In function ‘digitalWrite’:
wiringPi.c:1535:4: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
write (sysFds [pin], "0\n", 2) ;
^
wiringPi.c:1537:4: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
write (sysFds [pin], "1\n", 2) ;
^
wiringPi.c: In function ‘waitForInterrupt’:
wiringPi.c:1837:5: warning: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Wunused-result]
(void)read (fd, &c, 1) ; // Read & clear
^
wiringPi.c: In function ‘wiringPiISR’:
wiringPi.c:1953:5: warning: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Wunused-result]
read (sysFds [bcmGpioPin], &c, 1) ;
^
[Compile] mcp23016.c
[Compile] mcp23017.c
[Compile] mcp23s08.c
[Compile] mcp23s17.c
[Compile] sr595.c
[Compile] pcf8574.c
[Compile] pcf8591.c
[Compile] mcp3004.c
[Compile] mcp4802.c
[Compile] mcp3002.c
pcf8591.c: In function ‘myAnalogWrite’:
pcf8591.c:44:3: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
write (node->fd, b, 2) ;
^
[Compile] max31855.c
[Compile] mcp3422.c
[Compile] max5322.c
mcp3422.c: In function ‘waitForConversion’:
mcp3422.c:50:5: warning: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Wunused-result]
read (fd, buffer, n) ;
^
[Compile] ads1115.c
[Compile] sn3218.c
[Compile] bmp180.c
[Compile] htu21d.c
[Compile] ds18b20.c
[Compile] rht03.c
[Compile] drcSerial.c
[Compile] drcNet.c
[Compile] pseudoPins.c
[Compile] wpiExtensions.c
pseudoPins.c: In function ‘myAnalogRead’:
pseudoPins.c:50:16: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
int *ptr = (int *)node->data0 ;
^
pseudoPins.c: In function ‘myAnalogWrite’:
pseudoPins.c:59:16: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
int *ptr = (int *)node->data0 ;
^
pseudoPins.c: In function ‘pseudoPinsSetup’:
pseudoPins.c:89:17: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
node->data0 = (unsigned int)ptr ;
^
[Link (Dynamic)]
[Install Headers]
[Install Dynamic Lib]

WiringPi Devices Library
[UnInstall]
[Compile] ds1302.c
[Compile] maxdetect.c
[Compile] gertboard.c
[Compile] piFace.c
[Compile] piNes.c
[Compile] lcd.c
[Compile] lcd128x64.c
[Compile] scrollPhat.c
[Compile] piGlow.c
[Link (Dynamic)]
[Install Headers]
[Install Dynamic Lib]

GPIO Utility
[Compile] gpio.c
[Compile] readall.c
[Compile] pins.c
gpio.c: In function ‘doVersion’:
gpio.c:1292:7: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result]
fgets (name, 80, fd) ;
^
gpio.c: In function ‘doLoad’:
gpio.c:285:5: warning: ignoring return value of ‘system’, declared with attribute warn_unused_result [-Wunused-result]
system (cmd) ;
^
gpio.c:291:5: warning: ignoring return value of ‘system’, declared with attribute warn_unused_result [-Wunused-result]
system (cmd) ;
^
gpio.c: In function ‘doUnLoad’:
gpio.c:345:5: warning: ignoring return value of ‘system’, declared with attribute warn_unused_result [-Wunused-result]
system (cmd) ;
^
gpio.c:351:5: warning: ignoring return value of ‘system’, declared with attribute warn_unused_result [-Wunused-result]
system (cmd) ;
^
[Link]
[Install]

All Done.

NOTE: To compile programs with wiringPi, you need to add:
-lwiringPi
to your compile line(s) To use the Gertboard, MaxDetect, etc.
code (the devLib), you need to also add:
-lwiringPiDev
to your compile line(s).
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

[this]

@this I changed the version of qt and run it without errors.
The version I used was qt5.4.2.
I changed it to another version and it builds without errors.
Thank you for your help.

Is there a problem with qt5.4.2?
Hangul (Korean language) was also out of print, I had to worry about changing the version.
But wiringPi is also incompatible
Is there a problem with qt5.4.2 version?

[jsulm]

@this wiringPi isn't a Qt library to my knowledge, so it is not a Qt problem.
This is wrong:

LIBS += -L/usr/local/lib-lwiringPi

it must be:

LIBS += -L/usr/local/lib -lwiringPi

(space between lib and -l).
I really don't know what you are doing wrong. You should read http://doc.qt.io/qtcreator/creator-project-qmake-libraries.html
Also, "undefined reference" errors means that the a library (in your case wiringPi) is missing. Take a closer look at the compiler/linker output.
You can try to write a simple C++ console application without Qt but with wiringPi. Just create a makefile and build your app.

[this]

@jsulm Qt Build with no error when running with version 5.5.1.
However, when building with qt 4.5.2, the above error also occurs.
Is not this a version issue?
Space above the space is filled in.
I misplaced that article.

[jsulm]

@this Again: wiringPi is not a Qt library. In fact it is not even C++, it is a C library. You don't build it with Qt (Qt is not a compiler) you build it with a C compiler (gcc).
So what is the problem now: you can't build wiringPi or you can't build your Qt app which uses this lib?

[this]

@jsulm I am developing in qt.
So I need to build wiringPi using qt.

I think I can use wiringPi in qt.
WiringPi is a c language library.
So is it impossible to use in qt?
If I can not use wiringPi in qt, I will code it in another way for GPIO control.

If available in qt,
Having said that,
Ubuntu pc -> raspberrypi (rasbian)
I am developing using cross compile.
I am developing using qt 5.4.2.

I tried to continue but failed to recognize the wiringPi function.

So I tried qt 5.5.1.
Qt 5.5.1 is not a cross compile.
I run it on qt of ubuntu pc.

The same source and the same project.
Changed version and os of qt.
(Note that changing os does not mean that raspberrypi has built the program.
It refers to the os where the qt file is executed.)
It recognizes wiringPi without error.

So I think.
Whether wiringPi is compatible with the Qt version,
Whether wirignPi is not available depending on OS

Do you understand my situation now?