QDir mkpath returns true, but directory not created - c++

Question

I'm having a weird issue with creating paths using Qt on Linux. I've written a standalone test program that creates paths and tests for their existence. This works as expected and creates the directory.
/* make path */
QString p("/usr2/archive/S1234ABC/5/6");
QDir d;
if (d.mkpath(p)) qDebug() << "mkpath() returned true";
else qDebug() << "mkpath() returned false";
QDir d2;
if (d2.exists(p)) qDebug() << "exists() returned true";
else qDebug() << "exists() returned false";
I made that test example into a more robust function, in another project. But it isn't working... mkpath() and exists() return true, but the paths don't exist on the hard disk.
bool nidb::MakePath(QString p, QString &msg) {
if ((p == "") || (p == ".") || (p == "..") || (p == "/") || (p.contains("//")) || (p == "/root") || (p == "/home")) {
msg = "Path is not valid [" + p + "]";
return false;
}
WriteLog("MakePath() called with path ["+p+"]");
QDir path;
if (path.mkpath(p)) {
WriteLog("MakePath() mkpath returned true [" + p + "]");
if (path.exists()) {
WriteLog("MakePath() Path exists [" + p + "]");
msg = QString("Destination path [" + p + "] created");
}
else {
WriteLog("MakePath() Path does not exist [" + p + "]");
msg = QString("Unable to create destination path [" + p + "]");
return false;
}
}
else {
msg = QString("MakePath() mkpath returned false [" + p + "]");
return false;
}
return true;
}
The output from my program:
[2019/06/04 13:19:37][26034] MakePath() called with path [/usr2/archive/S0836VYL/6/5/dicom]
[2019/06/04 13:19:37][26034] MakePath() mkpath returned true [/usr2/archive/S0836VYL/6/5/dicom]
[2019/06/04 13:19:37][26034] MakePath() Path exists [/usr2/archive/S0836VYL/6/5/dicom]
and the output from the command line...
[onrc#ado2dev /]$ cd /usr2/archive/S0836VYL/6/5/dicom
-bash: cd: /usr2/archive/S0836VYL/6/5/dicom: No such file or directory
[onrc#ado2dev /]$
What am I missing??

Answer 1

Try to use this :
QString p("/usr2/archive/S1234ABC/5/6");
QDir d(p);
if(!d.exists() && !d.mkpath(p)) qDebug() << "Error: can't create folder '"<< p <<"'.";
else qDebug() << "Folder '"<< p <<"' exists or created successfully".
Hope it helps you.

Answer 2

All right, this is one for the record books...
The issue was a null terminator appended to the end of the S1234ABC string before being inserted into the database. That string was later used to create the above paths. That S1234ABC string was created using the following code:
QString prefix = "S";
QChar C1, C2, C3, etc... (randomly generated characters)
QString newID = prefix + C1 + C2 + etc...
This created a QString with a \0 on the end of it. Qt stored this value in the MySQL database, which I then pulled back into Qt and tried to make a path with it. Since it's a null terminated string, it appears normal on phpMyAdmin, in xterm, and the log files. Except... in puTTY in Windows, where I saw the weird path it was trying to create:
/usr2/archive/S0836VYL\u0000/10/3/dicom
Thankfully puTTY displayed the actual unicode value instead of ignoring it. Thank you putty! I never, ever would've figured that out...
Recreating the S1234ABC string using QStrings for each character instead of QChar fixed the issue. Now I have regular old strings in the database, and normal paths.