Automatic Build in Sublime Text is not working for C++ - c++

Question

I have created the Custom Build System for C++ file. Below is my Build System:
{
"cmd": ["g++", "-Wall", "-time", "$file", "-o", "$file_base_name","&&", "start", "cmd","/c","${file_base_name}","^&","cmd","/c","pause"],
"file_regex": "^[ ]*File \"(...*?)\", line ([0-9]*)",
"working_dir": "${project_path:${folder}}",
"selector": "source.cpp",
"shell": true,
}
The thing is, it is working only if I select this build system manually. If I specify Automatic build system, the system's c++ build system is working instead of mine. How to change this behavior?

Answer 1

According to documentation:
example:
{
"cmd": ["python", "-u", "$file"],
"file_regex": "^[ ]*File \"(...*?)\", line ([0-9]*)",
"selector": "source.python"
}
selector
Optional. Used when Tools | Build System | Automatic is set to true. Sublime Text uses this scope selector to find the appropriate build system for the active view.
So "selector": "source.cpp", is the part responsible for choosing build system. In other place we read:
Sublime Text implements the idea of scopes from Texmate, a text editor for Mac. Textmate’s online manual contains further information about scope selectors that’s useful for Sublime Text users too.
On Textmate documentation:
As with CSS, it is possible to use the context of an element in the scope selector. The picture below shows the scope for the string as a tool tip (via ⌃⇧P). The direct parent of the string is source.php.embedded.html and text.html.basic is an ancestor.
In the scope selector we specify element names as a space separated list to indicate that each element should be present in the scope (and in the same order). So if we want to target all strings in PHP, we can use source.php string, or we can use text.html source.php to target PHP embedded in HTML.
Notife that scope doesn't mean filename not extension. In C++.sublime-project you have:
C++.sublime-settings{
"extensions": ["cpp", "cc", "cxx", "c++", "h", "hpp", "hxx", "h++", "inl", "ipp"]
}
which make files with those extensions in scope of c++. Changing your scope definition to "selector": "source.c++" should run your builder if your currently opened file is recognized as belonging to the C++ scope.