Question

The process method is not working if I pass the user home directory programmatically in windows XP and windows 32 bit systems

The below code works fine:

 QProcess process;
 process.execute("C:/DOCUME~1/pjo/myprok/tmp/APP.exe");

Not working Code:

Here I am getting the path of the APP.exe using QDir::homePath

    process.execute("C:/Documents and Settings/pjo/myprok/tmp/APP.exe");

The errorString returns “UnKnown error”

I tried with start method also which never works:

B Not working Code:

    process.start("C:/Documents and Settings/pjo/myprok/tmp/APP.exe");

Error: Path Not found

    process.start("C:/DOCUME~1/pjo/myprok/tmp/APP.exe");

Error : Unknown error

Answer 1

Your issue is probably due quoting issues caused by the spaces in the path (C:\Documents and Settings…).
Note that there are two overloads for start():

void    start ( const QString & program, OpenMode mode = ReadWrite )
void    start ( const QString & program, const QStringList & arguments, OpenMode mode = ReadWrite )

You are using the first, which takes the executable path and all args in one string, and expects it to be quoted correctly. Without quoting, “c:\documents” is interpreted as the executable and “and” “Settings…” etc. as the arguments.

The second version takes the arguments separately, and will interpret the executable path correctly, without any quoting needed. Thus, the easiest way is to use

process.start("C:/Documents and Settings/pjo/myprok/tmp/APP.exe", QStringList());

This ensure the second version to be used, and should save you from all quoting issues.
I suggest to always use that overload.

The same applies to execute(), which is, as already said, a static method, so the error codes of the QProcess object won’t be set.