使用 QProcess 启动另一个 exe 并生成路径错误的文件

Question

I met a question recently. I use QProcess class to start B.exe in A.pro . The absolutely path of A.pro is C:/QT/A/A.pro . I use windeployqt to package B.exe , and put the package folder in C:/QT/A/B/B.exe .

In B.exe , the program will generate a file named test.json . The test.json 's path is the same as B.exe . But I use follows codes in A.pro , the test.json is generated to the path the same as A.pro but not in folder C:/QT/A/B :

bool f = QProcess::startDetached("./B/B.exe");

The line code return true . I think test.json should generated in folder C:/QT/A/B but not in C:/QT/A . When I double click B.exe standlone, it can generate correctly. But when I debug with code above in A.pro , it works failed and it just created a empty file.

Can you help me?

Answer 1

If you look into QProcess::startDetached , it reads as follows:

The process will be started in the directory workingDirectory. If workingDirectory is empty, the working directory is inherited from the calling process.

You need to set working directory for QProcess . When you run B.exe by "double clicking" it. Your OS sets the working dir from where it was started, ie, C:/QT/A/B . But when you start it from A.exe, its working directory is C:/QT/A/

You can read about QProcess::setWorkingDirectory here . But since, you are running it with QProcess::startDetached overload, you just need to pass wanted working directory as a parameter:

bool f = QProcess::startDetached("./B/B.exe", QStringList(), "./B/");