<p>How can I programmatically lock/unlock, or otherwise prevent/enable editing, a source file on Linux using C++.</p>

<p>I want to be able to lock source file so that if I open it in an editor it will not allow me to save back to the same source file.</p>

<p>I am thinking of maybe changing the permissions to read-only (and change it back to read-write later): how do I do that from C++?</p>

Try man fchmod:
```
NAME
       chmod, fchmod - change permissions of a file

SYNOPSIS
       #include <sys/types.h>
       #include <sys/stat.h>

       int chmod(const char *path, mode_t mode);
       int fchmod(int fildes, mode_t mode);
```