5.6 Interrupting or Killing `make'==================================If `make' gets a fatal signal while a shell is executing, it may deletethe target file that the recipe was supposed to update.  This is doneif the target file's last-modification time has changed since `make'first checked it.   The purpose of deleting the target is to make sure that it is remadefrom scratch when `make' is next run.  Why is this?  Suppose you type`Ctrl-c' while a compiler is running, and it has begun to write anobject file `foo.o'.  The `Ctrl-c' kills the compiler, resulting in anincomplete file whose last-modification time is newer than the sourcefile `foo.c'.  But `make' also receives the `Ctrl-c' signal and deletesthis incomplete file.  If `make' did not do this, the next invocationof `make' would think that `foo.o' did not require updating--resultingin a strange error message from the linker when it tries to link anobject file half of which is missing.   You can prevent the deletion of a target file in this way by makingthe special target `.PRECIOUS' depend on it.  Before remaking a target,`make' checks to see whether it appears on the prerequisites of`.PRECIOUS', and thereby decides whether the target should be deletedif a signal happens.  Some reasons why you might do this are that thetarget is updated in some atomic fashion, or exists only to record amodification-time (its contents do not matter), or must exist at alltimes to prevent other sorts of trouble.