Qt5.9.2 for RPi3. Here the current target scenario:
# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.167 netmask 255.255.0.0 broadcast 192.168.255.255
inet6 fd00::b465:a62:a349:a7a5 prefixlen 64 scopeid 0x0<global>
inet6 fe80::dbfe:16c3:a5cd:9509 prefixlen 64 scopeid 0x20<link>
ether b8:27:eb:22:00:43 txqueuelen 1000 (Ethernet)
RX packets 338 bytes 44737 (43.6 KiB)
RX errors 0 dropped 1 overruns 0 frame 0
TX packets 238 bytes 27565 (26.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 40 bytes 8560 (8.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 40 bytes 8560 (8.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.179 netmask 255.255.0.0 broadcast 192.168.255.255
inet6 fd00::2eed:5f16:9646:fe07 prefixlen 64 scopeid 0x0<global>
inet6 fe80::c460:6252:ee34:8695 prefixlen 64 scopeid 0x20<link>
ether 00:c6:b1:8f:a1:38 txqueuelen 1000 (Ethernet)
RX packets 149 bytes 45709 (44.6 KiB)
RX errors 0 dropped 97 overruns 0 frame 0
TX packets 106 bytes 17632 (17.2 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Here my code that should retrieve the IPv4 addresses:
const QHostAddress &localhost = QHostAddress(QHostAddress::LocalHost);
for (const QNetworkInterface &interface: QNetworkInterface::allInterfaces())
{
QString name = interface.name();
for (const QHostAddress &address: interface.allAddresses())
{
if (address.protocol() == QAbstractSocket::IPv4Protocol && address != localhost && (interface.flags() & QNetworkInterface::IsRunning))
qDebug() << name << address << interface.flags();
}
}
Here the output:
"lo" QHostAddress("192.168.1.167") QFlags(0x1|0x2|0x8)
"lo" QHostAddress("192.168.1.179") QFlags(0x1|0x2|0x8)
"eth0" QHostAddress("192.168.1.167") QFlags(0x1|0x2|0x4|0x20)
"eth0" QHostAddress("192.168.1.179") QFlags(0x1|0x2|0x4|0x20)
"wlan0" QHostAddress("192.168.1.167") QFlags(0x1|0x2|0x4|0x20)
"wlan0" QHostAddress("192.168.1.179") QFlags(0x1|0x2|0x4|0x20)
Instead, according to ifconfig, I'm expecting only:
"eth0" QHostAddress("192.168.1.167") QFlags(0x1|0x2|0x4|0x20)
"wlan0" QHostAddress("192.168.1.179") QFlags(0x1|0x2|0x4|0x20)
Is my code wrong?
As the documentation of QNetworkInterface::allInterfaces says:
This convenience function returns all IP addresses found on the host machine.
Note: The emphasis is mine.
This means, that with two interfaces, your code will essentially loop through the addresses twice.
Use QNetworkInterface::addressEntries instead. Then use QNetworkAddressEntry::ip to obtain the information you need.
Here is an example implementation of the proposed solution:
for (auto interface : QNetworkInterface::allInterfaces()) {
for (auto address : interface.addressEntries()) {
const QHostAddress &ip(address.ip());
if (!ip.isLoopback() && (ip.protocol() == QAbstractSocket::IPv4Protocol) && (interface.flags() & QNetworkInterface::IsRunning))
qDebug() << interface.humanReadableName() << ip.toString();
}
}