public inbox for gcc-prs@sourceware.org help / color / mirror / Atom feed
From: D.Yu.Bolkhovityanov@inp.nsk.su To: gcc-gnats@gcc.gnu.org Subject: preprocessor/3872: gcc -M... ignores "-o" Date: Mon, 30 Jul 2001 00:36:00 -0000 [thread overview] Message-ID: <20010730072935.2959.qmail@sourceware.cygnus.com> (raw) >Number: 3872 >Category: preprocessor >Synopsis: gcc -M... ignores "-o" >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: sw-bug >Submitter-Id: net >Arrival-Date: Mon Jul 30 00:36:00 PDT 2001 >Closed-Date: >Last-Modified: >Originator: D.Yu.Bolkhovityanov@inp.nsk.su >Release: gcc version 2.96 20000731 (Red Hat Linux 7.1 2.96-85) >Organization: >Environment: >Description: When gcc is ran with a following command line gcc -M sourcefile.c -o depfile.dep it prints a list of dependencies to stdout instead of "depfile.dep" (any "-M..." option may be used instead of just "-M" -- e.g. "-MM"). What it uses "-o" for is a filename before ":" in depfile -- i.e. there will be "depfile.dep: ..." instead of "sourcefile.o: ...". In earlier versions (since ancient and at least up to egcs-2.91) this worked as expected. Such a behaviour seems even more strange if taking into account a note in ChangeLog.CPP for 2001-01-08: "If -o given, use it as the target of any -M options" (or is *that* a cause of the bug?) Sure, one can use ">depfile.dep" instead, but that's not a good idea, and I'll try to explain why. When "gcc -M ..." is run from Makefile, and when cpp encounters an error (e.g. missing file in #include), in case of working "-o depfile.dep" it wouldn't touch depfile.dep, while in case of ">depfile.dep" the timestamp on the latter will become more recent than that of "sourcefile.c", and hence the immediately repeated "make" will "succeed" (since it wouldn't run "gcc -M..." at all). Of course, the subsequent "gcc" w/o "-M" will fail, but such behaviour is undesired anyway. >How-To-Repeat: Issue the following commands: echo "#include <stdio.h>" >sourcefile.c gcc -E -M sourcefile.c -o depfile.dep and you'll get a text describing "depfile.dep" (!!!) dependant on many system headers. The "depfile.dep" isn't created as it should. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2001-07-30 0:36 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2001-07-30 0:36 D.Yu.Bolkhovityanov [this message] 2001-07-30 0:48 neil 2002-03-15 3:28 neil
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20010730072935.2959.qmail@sourceware.cygnus.com \ --to=d.yu.bolkhovityanov@inp.nsk.su \ --cc=gcc-gnats@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).