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GNU Info (make.info)InterruptsInterrupting or Killing `make' ============================== If `make' gets a fatal signal while a command is executing, it may delete the target file that the command was supposed to update. This is done if 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 remade from 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 an object file `foo.o'. The `Ctrl-c' kills the compiler, resulting in an incomplete file whose last-modification time is newer than the source file `foo.c'. But `make' also receives the `Ctrl-c' signal and deletes this incomplete file. If `make' did not do this, the next invocation of `make' would think that `foo.o' did not require updating--resulting in a strange error message from the linker when it tries to link an object file half of which is missing. You can prevent the deletion of a target file in this way by making the 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 deleted if a signal happens. Some reasons why you might do this are that the target is updated in some atomic fashion, or exists only to record a modification-time (its contents do not matter), or must exist at all times to prevent other sorts of trouble. automatically generated by info2www version 1.2.2.9 |