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Re: make bin got dumb because of "Fix description in lily/include/smobs.

From: Werner LEMBERG
Subject: Re: make bin got dumb because of "Fix description in lily/include/smobs.hh"
Date: Tue, 03 Jul 2012 23:57:05 +0200 (CEST)

> It is almost certainly a problem with your system clock.  If you have
> touched source files with a future clock, and now the clock is right,
> then compiled files will be outdated ("older" than the source file)
> immediately after compilation again.

There is a special built-in target in GNU make:

     If you specify prerequisites for `.LOW_RESOLUTION_TIME', `make'
     assumes that these files are created by commands that generate
     low resolution time stamps.  The recipe for the
     `.LOW_RESOLUTION_TIME' target are ignored.

     The high resolution file time stamps of many modern file systems
     lessen the chance of `make' incorrectly concluding that a file is
     up to date.  Unfortunately, some hosts do not provide a way to
     set a high resolution file time stamp, so commands like `cp -p'
     that explicitly set a file's time stamp must discard its
     subsecond part.  If a file is created by such a command, you
     should list it as a prerequisite of `.LOW_RESOLUTION_TIME' so
     that `make' does not mistakenly conclude that the file is out of
     date.  For example:

          .LOW_RESOLUTION_TIME: dst
          dst: src
                  cp -p src dst

     Since `cp -p' discards the subsecond part of `src''s time stamp,
     `dst' is typically slightly older than `src' even when it is up
     to date.  The `.LOW_RESOLUTION_TIME' line causes `make' to
     consider `dst' to be up to date if its time stamp is at the start
     of the same second that `src''s time stamp is in.

Maybe this helps?


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