带有 Qt 的 C++ 编译失败

Question

I'm trying to compile the following short C++ program (not written by me) in Debian:

$ cat checksig.cpp
#include <QByteArray>
#include <QDebug>

#include <openssl/ec.h>
#include <openssl/evp.h>
#include <openssl/ecdsa.h>
#include <openssl/sha.h>

static EC_KEY* EC_KEY_pub_key ( const QByteArray& pub )
{
  static EC_KEY* eckey = EC_KEY_new_by_curve_name ( NID_secp256k1 );
  const quint8* ppub = (const quint8*)pub.constData ( );
  o2i_ECPublicKey ( &eckey, &ppub, pub.size ( ) );
  return eckey;
}
//--------------------------------------------------------------
int main(int argc, char *argv[])
{
  const QByteArray data ( QByteArray::fromHex ( argv [1] ) );
  const QByteArray sign ( QByteArray::fromHex ( argv [2] ) );
  const QByteArray pubk ( QByteArray::fromHex ( argv [3] ) );

  quint8 tmp [32];
  ::SHA256 ( (const quint8*)data.constData ( ), data.size ( ), tmp );
  quint8 digest [32];
  ::SHA256 ( tmp, 32, digest );
  qDebug ( ) << "data=" << QString ( data.toHex ( ) );
  qDebug ( ) << "sign=" << QString ( sign.toHex ( ) );
  qDebug ( ) << "pubk=" << QString ( pubk.toHex ( ) );

  qDebug ( ) << "digest=" << QString ( QByteArray ( (const char*)digest, 32 ).toHex ( ) );

  const bool v ( ::ECDSA_verify ( 0, digest, 32, (const quint8*)sign.constData ( ), sign.size ( ), EC_KEY_pub_key ( pubk ) ) );
  qDebug ( ) << "result=" << v;

  return 0;
}

But I don't think I'm using the right includes, or maybe I need to install more Qt libraries?

$ g++ -Wall checksig.cpp -o checksig -L /usr/include/i386-linux-gnu/qt5/QtCore/ -lQtCore -I /usr/include/i386-linux-gnu/qt5/QtCore/
In file included from /usr/include/i386-linux-gnu/qt5/QtCore/QByteArray:1:0,
from checksig.cpp:4:/usr/include/i386-linux-gnu/qt5/QtCore/qbytearray.h:45:30: fatal error: QtCore/qrefcount.h: No such file or directory
#include <QtCore/qrefcount.h>
                             ^

and alternatively, using includes and libraries from one directory back:

g++ -Wall checksig.cpp -o checksig -L /usr/include/i386-linux-gnu/qt5/ -lQtCore -I /usr/include/i386-linux-gnu/qt5/
checksig.cpp:4:22: fatal error: QByteArray: No such file or directory
#include <QByteArray>
                      ^
compilation terminated.

I'm new to C++. How can I compile this small program in a 1-liner?

---

As requested in the comments:

$ sudo apt-file search "QtCore/qrefcount.h"
qtbase5-dev: /usr/include/i386-linux-gnu/qt5/QtCore/qrefcount.h

---

thanks to Michael Popovich 's answer i tried the following and got further. but now i have new errors:

$ g++ -Wall checksig.cpp -o checksig -L /usr/include/i386-linux-gnu/qt5/QtCore/ -lQtCore -I /usr/include/i386-linux-gnu/qt5/ -I /usr/include/i386-linux-gnu/qt5/QtCore/
In file included from /usr/include/i386-linux-gnu/qt5/QtCore/qatomic.h:42:0,
                 from /usr/include/i386-linux-gnu/qt5/QtCore/qrefcount.h:45,
                 from /usr/include/i386-linux-gnu/qt5/QtCore/qbytearray.h:45,
                 from /usr/include/i386-linux-gnu/qt5/QtCore/QByteArray:1,
                 from checksig.cpp:4:
/usr/include/i386-linux-gnu/qt5/QtCore/qglobal.h:1034:4: error: #error "You must build your code with position independent code if Qt was built with -reduce-relocations. " "Compile your code with -fPIC or -fPIE."
 #  error "You must build your code with position independent code if Qt was built with -reduce-relocations. "\
    ^

i have no idea if qt was built with -reduce-relocations i don't think i even installed it myself - it was probably pulled in as a dependency for another install.

anyway, trying with -fPIC and -fPIE :

$ g++ -Wall checksig.cpp -o checksig -L /usr/include/i386-linux-gnu/qt5/QtCore/ -lQtCore -I /usr/include/i386-linux-gnu/qt5/ -I /usr/include/i386-linux-gnu/qt5/QtCore/ -fPIC
/usr/bin/ld: cannot find -lQtCore
collect2: error: ld returned 1 exit status
$ g++ -Wall checksig.cpp -o checksig -L /usr/include/i386-linux-gnu/qt5/QtCore/ -lQtCore -I /usr/include/i386-linux-gnu/qt5/ -I /usr/include/i386-linux-gnu/qt5/QtCore/ -fPIE
/usr/bin/ld: cannot find -lQtCore
collect2: error: ld returned 1 exit status

Answer 1

Check #find /usr/include/i386-linux-gnu/qt5/ -name qrefcount.h

Add result path to QtCore/ in your project or your system PATH

Answer 2

I'd recommend to build Qt with either CMake or QMake, here is the solution with QMake:

checksig.pro :

QT += core

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = checksig
TEMPLATE = app

SOURCES += checksig.cpp

LIBS += -lssl -lcrypto

And compile like this:

qmake checksig.pro
make

Will compile a correct binary.

---

And if you really need some 1-liner:

g++ checksig.cpp -o checksig -fPIC -isystem /usr/include/x86_64-linux-gnu/qt5 -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -lssl -lcrypto -lQt5Core -lpthread

Answer 3

For people like me, that uses windows OS and they accidently came to this page and the above solutions did not solve their problem, can try the following solution:
I downloaded the OpenSSL executable from the official website , and selected the file with the description that contanins the following line ( Recommended for software developers by the creators of OpenSSL ).
At the time of writing this solution, the file version is (Win64 OpenSSL v3.0.0), and it can be directly downloaded from the following link .

Here is an Image for more declaration:

After that, I did the following steps:

1. Install the OpenSSL form the .exe file.
2. Copy the bin folder directory path (in my case it was C:\\Program Files\\OpenSSL-Win64\\bin) and add it to the system enviroment variables.
3. Copy the include folder directory path (in my case it was C:\\Program Files\\OpenSSL-Win64\\include) and add it to the system enviroment variables.

Then compile the source code that used the openssl library and header files, they should be compiled with no errors.