> Date: Tue, 16 Apr 2013 05:54:13 +0000 > From: "Paul D. Smith" <invalid.nore...@gnu.org> > > I did a little bit of code rearrangement, but I still think this code will not > work on Windows and might possibly not compile on Windows.
Indeed, it will not. Some cursory comments below. > Hopefully we can fix that. We shall see... Here's what I see in the changes that is not friendly to Windows: . STREAM_OK uses fcntl and F_GETFD which both don't exist on Windows. . FD_NOT_EMPTY will only work if its argument descriptor is connected to a file, not the console. is this condition always true? . open_tmpfd will need close examination on Windows, especially since it closes the stream (the issue is whether the file will still be automatically deleted when the dup'ed file descriptor is closed). . pump_from_tmp_fd will need to switch to_fd to binary mode, since this is how tmpfile opens the temporary file; we need output mode match the input mode. . acquire_semaphore uses fcntl and F_SETLKW, which don't exist on Windows. the commentary to that function is not revealing its purpose, so I'm unsure how to implement its equivalent on Windows. can someone explain why is this needed and what should it do? the name seems to imply that using fcntl is an implementation detail, as a crude semaphore -- is that right? similarly for release_semaphore. (see also the next item.) . is there any significance to the fact that sync_handle is either stdout or stderr? is that important for the synchronization to work, or was that just a convenient handle around? also, the documentation I have indicates that locking works only on files; is it guaranteed that these handles are redirected to files before acquire_semaphore is called? . calculation of combined_output in start_job_command will need to be reimplemented for Windows, since the reliance on st_dev and st_ino makes assumptions that are false on Windows. Other notes: . outputting stdout and stderr separately is IMO a misfeature: it breaks the temporal proximity of messages written to these streams, and this makes it harder to understand failures. . why is "leaving directory FOO" displayed _before_ releasing the stderr output? it should be after, I think. . AFAIU, the call to fcntl inside sync_output can be interrupted by a signal, and will return -1. shouldn't the code do something non-trivial to avoid a total failure in this case? . suggest to use "acquire_semaphore" and "release_semaphore" in the call to perror in those two functions, as "fcntl" is not specific enough, and also reveals implementation details. . likewise, "read()" and "write()" in diagnostics from pump_from_tmp_fd are less specific than they could be; how about "read from temporary file" instead? . btw, why an error in acquire_semaphore and release_semaphore causes Make to bail out? isn't it better to fall back on the normal operation mode instead? . I don't understand why PARLLEL_SYNC is turned on unconditionally in job.h based on POSIX being defined. it should IMO be in config.h instead, set at configure time. . the new argument to log_working_directory is not documented in the commentary to the function. Thanks. _______________________________________________ Bug-make mailing list Bug-make@gnu.org https://lists.gnu.org/mailman/listinfo/bug-make
