gcc compiling tips
This is good general advice on code porting.
I would add a few things. First, you may not need to port - the Linux abi may allow you to run your program without porting. However, there still may be hard paths and references to non-existent programs (or worse, references to programs that exist but have different function!)
I'd recommend reading Advanced Programming in the Unix Environment and be aware that "make" files that say they provide support for your target OS may be a good natured guess by someone trying to be helpful - they may never have actually compiled on that system!
From - Fri Sep 24 15:36:26 1999 Xref: world comp.unix.sco.misc:106012 Path: world!newsfeed.mathworks.com!btnet-peer!btnet!newspeer.clara.net!news.clara.net!peer.news.zetnet.net!peer.news.bb.u-net.net!u-net!yama.mcc.ac.uk!cs.man.ac.uk!smallshaw From: [email protected] (Andrew Smallshaw) Newsgroups: comp.unix.sco.misc Subject: Re: gcc compiling notes Date: 24 Sep 1999 14:51:25 GMT Organization: Dept of Computer Science, University of Manchester, U.K. Lines: 61 Message-ID: <[email protected]> NNTP-Posting-Host: ug029.cs.man.ac.uk NNTP-Posting-User: smallsa7 User-Agent: slrn/0.9.5.4 (UNIX) X-Mozilla-Status: 8011 On Fri, 24 Sep 1999 01:00:30 -0400, Brian K. White wrote: > Is there a repository of porting/compiling notes for compiling various > free apps on OS 5.0.5 using gcc? > I didn't include detailed make error messages because I'm not really > looking for help with libjpeg. I'm looking for help with 'stuff' the > general points to see to in any random makefile for super whiz-bang gnu > app xyzX When it comes to porting, it's helpful to know APIs of various Unix systems inside out and back to front, but the best way of doing this is probably by porting. It appears you want general pointers on porting so a few tips: 1) Link errors If you successfully compile an application but get errors on linking, do a 'man function-name' for the missing function. In the syntax section, you'll see a line 'cc ... -l(library)'. You need to add the -l bit to get the required library linked in. 2) Apparently missing functions It's possible that what is needed is there, but defined in a place other than where the program expects it. 'man function-name' will tell you what headers you need to pick up the function declaration. 3) Apparently missing #defines and/or variables Again, these may be present, but in a non-standard location. Try searching scohelp for the term you're looking for, and include the relevant headers. Alternatively you can find and grep on /usr/include, /usr/local/include, etc. 4) Really missing functions, #defines, or variables These fall into two categories: those that are included in other Unix systems, and those that belong to third party libraries. Third party libraries first: find out which library you need, get it and port that. This can get a bit demoralising when you have to port several libraries before you can get on with what you're trying to do. Other systems: read up on what the function in question does (most Unixes have on-line docs somewhere on the net), and assess how tricky it will be to implement. Some times you can create a simple wrapper around facilities you do have, or you may have to re-write the problematic code to use your system's facilities. 5) #ifdefs These are your friends. You may have done a './configure', but the #defines still may not be quite right. Look around the problematic code and see if there are any #ifdefs that look like they could solve your problem. If so this is likely to prove the path of least resistance. This isn't exhaustive, of course. Feel free to add extra points here. -- Andrew Smallshaw [email protected]
From - Mon Jun 19 06:30:17 2000 Path: news.randori.com!hermes.visi.com!news-out.visi.com!newsfeed.direct.ca!newsfeed.icl.net!colt.net!news0.de.colt.net!bignews.mediaways.net!news.vew-telnet.net!news.st-oneline.de!not-for-mail From: Frank Langelage <[email protected]> Newsgroups: comp.unix.sco.misc Subject: Re: [Question] about my LINK errors Date: Sun, 18 Jun 2000 21:40:56 +0200 Organization: ST-oneline InterNet Service Provider GmbH Lines: 67 Message-ID: <[email protected]> References: <[email protected]> NNTP-Posting-Host: line4.st-oneline.de Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Server-Date: 18 Jun 2000 19:46:31 GMT X-Mailer: Mozilla 4.61 [de] (X11; I; UnixWare 5 i386) Xref: news.randori.com comp.unix.sco.misc:61946 X-Mozilla-Status: 8010 X-Mozilla-Status2: 00000000 The order the libraries are named for the link command is wrong. -lm is behind lgasrfeat.a. You can add -lm at the and a second time or put your own libraries in front of the system libs. cc voice.o process.o ifunc.o util.o msg_q.o vms.o vms_sub.o ars1.o ars2.o v_ad.o vms_util.o paramete.o sctools.o guide.o ipc_ex.o faxutil.o fax.o q_call.o log.o lgasrfeat.a -ldti -ldxyz -lsrl -lm -lfax -lcurses -lsocket -lc -lgthreads /usr/lib/libgthreads.a -o voice
From - Tue Jun 20 17:58:11 2000 Path: news.randori.com!hermes.visi.com!news-out.visi.com!feeder.via.net!news.he.net!cyclone-transit.snfc21.pbi.net!184.108.40.206!hobbes.sco.com!kauai!jls From: [email protected] (J. L. Schilling) Newsgroups: comp.unix.sco.misc,comp.unix.sco.programmer Subject: Re: warning: #ident is an extension of ANSI C Followup-To: comp.unix.sco.misc,comp.unix.sco.programmer Date: 20 Jun 2000 20:15:08 GMT Organization: SCO, Inc. Lines: 17 Message-ID: <[email protected]> References: <[email protected]> Reply-To: [email protected] NNTP-Posting-Host: kauai.newjersey.sco.com X-Newsreader: TIN [version 1.2 PL2] Xref: news.randori.com comp.unix.sco.misc:62046 comp.unix.sco.programmer:6414 X-Mozilla-Status: 8010 X-Mozilla-Status2: 00000000 Jeff Dickens ([email protected]) wrote: : Recently we moved to version 5.0.5. Now we get warnings like this: : "/usr/include/stdlib.h", line 226: warning: #ident is an extension of ANSI C : [...] This is a "feature" of the cc -w3 option (highest level warnings). #ident is indeed not part of strict ANSI C, although warning you about things inside system headers (which you have no control over) is admittedly not very practical. To eliminate these warnings, use cc -w2 or less. -- Jonathan Schilling SCO, Inc. [email protected]
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