Very Computer

This is I hope the definitive FAQ for most GCC queries I have seen on the net.

Please read this before you post. It should hopefully reduce noise on this
channel.

Mitch

---------------------------Linux GCC FAQ--------------------------

1) How do I tell what version of GCC I am using ?
2) Where is the latest distribution of GCC, as, ld, ar,  etc.. ?
3) Where can I find the newest shared libraries libc.so and libm.so ?
4) What other shared libraries are available for Linux ?
5) How do I build a shared DLL library for Linux ?
6) Why do I get the message "PLT__oct__FUii" when I execute a certain binary ?
7) How do I build a cross compiler on platform XXX to produce code for Linux ?
8) What symbols are automatically defined by Linux's GCC ?
9) How do I get over BSD'isms (especially signals, sigvec etc..) when compiling code ?
10) Where are SIGBUS, SIGEMT, SIGIOT, SIGTRAP, SIGSYS  etc ?
11) What is libhard and libsoft ?
12) What does the message "can't load library: /lib/libxxx.so, Incompatible version" mean ?
13) Why are my binaries so huge and how do I reduce them ?
14) What does the -N flag do, and when should I use it ?
15) How do I get debugging information into a program ?
16) What debuggers are available for Linux ?
17) How do I debug a daemon program ?
18) What is profiling and how do I profile a program ?
19) Is there a way to tell if a binary is linked  statically or to a shared library ?
20) Does Linux have support for LD_LIBRARY_PATH ?
21) My program wants /lib/cpp ! Where can I get it from ?
22) Where is <varargs.h> ?
23) My program wants to include <linux/foo.h> but cannot find it, where is it ?
24) Do we have the function foo() in our libraries ?
25) How do I port program XXX to Linux ?
26) I think I have found a bug in gcc/library foo, what do I do now ?
27) Why are shared libraries so large in comparison to their static counterparts ?
28) What are .sa file I see in /usr/lib ?
29) Where can I get Objective C for Linux ?
30) What does the message "Internal compiler error: cc1 got fatal signal 11" mean ?
31) What is a libc.so.lite ?
32) Does Linux libraries have SHADOW Password support, and how do I switch it on/off ??
33) Can't find math.h routines ! My program compiles but cannot find log(), sin(), etc.., HELP !!
34) Is there a manual for GCC? If so, where do I get it, and how do I print it out ?
35) I get the message "Undefined symbol _bsd_ioctl". Where is this anyhow ??

----------------------------------------------------------------

1) How do I tell what version of GCC I am using ?

Ans:    Execute the command
                gcc -v
        to find out what version you are using. At the time of writing the
        above command produces on my machine
                Reading specs from /usr/lib/gcc-lib/i386-linux/2.4.0/specs
                gcc version 2.4.0
        You would be well advised to upgrade to a version similar to this or
        above.

        P.S. If you get the output
                Reading specs from /usr/lib/gcc-lib/i486-linux/2.4.0/specs
                gcc version 2.4.0
        you are running a gcc compiled for a 486.

----------------------------------------------------------------

2) Where is the latest distribution of GCC, as, ld, ar,  etc.. ?

Ans:    The Official place for GCC distributions is tsx-11.mit.edu in
        /pub/linux/packages/GCC. All others sites mirror this.
        The latest versions of all GCC stuff will be found here.

        At the time of writing the latest GCC is version 2.4 from
                tsx-11.mit.edu:/pub/Linux/GCC/a-gcc-2.4.0.tar.z

----------------------------------------------------------------

3) Where can I find the newest shared libraries libc.so and libm.so ?

Ans:    See (2) above. You need the file image*.tar.z. For 486 images look
        under /pub/linux/packages/GCC/486.

----------------------------------------------------------------

4) What other shared libraries are available for Linux ?

Ans:    Ok here is a list I have been compiling. Any additions/changes
        graciously received.

        The locations given below were where they were last seen (or
        reportedly seen). They may have been moved by archive maintainers.

        P.S. The descriptions of the libraries may not be obvious. I will
        add descriptions in a later table (i.e. when all are filled). Please
        send descriptions of the libraries (except the obvious) if you know
        what they are.

Here are the locations of currently registered DLL libraries for Linux.
======================================================================

libc.so         sunsite.unc.edu:/pub/Linux/GCC/image-4.4.tar.z
libm.so                 included in above tar.z file.

libX11.so       tsx-11.mit.edu:pub/linux/packages/X11/XFree86-1.2/x1.2.base.tpz
libXt.so                included in above tpz file.
libXaw.so               included in above tpz file.

librl.so        sunsite.unc.edu:/pub/Linux/libs/librl-1.1.tar.z
libgr.so        sunsite.unc.edu:/pub/Linux/libs/libgr-1.2.tar.z
libf2c.so       sunsite.unc.edu:/pub/Linux/development/fortran/libf2c-0.7.tar.z
libF77.so               use libf2c.so instead.
libI77.so               use libf2c.so instead.

libXpm.so       sunsite.unc.edu:/pub/Linux/libs/libXpm32g.tar.z
libnet.so       redundant (reintegrated into libc.so address space
librpc.so                               to be used for nis/yp and rpcsvc)

libolgx.so      sunsite.unc.edu:/pub/Linux/X11/devel/xview3l4.tar.z
libxview.so             included in above tar.z file.
libsspkg.so             included in above tar.z file.
libUIC.so               included in above tar.z file.

libPEX.so

libtcl.so       sunsite.unc.edu:/pub/Linux/development/tcl/tclDist.tar.z
libtk.so                included in above tar.z file.

libWc.so
libXp.so

libIV.so
libUnidraw.so

libXm.so(motif) Not free. See note below.

libsrgp.so      sunsite.unc.edu:/pub/Linux/X11/devel/suit.tpz
libsuit.so              included in above tpz file.

------------
Note:-

Drop in DLL libraries for Xaw to get a 3d effect (libXaw3d-0.6) and a Mac(TM)
like scroll bar on Xaw clients are available respectively at

        sunsite.unc.edu:/pub/Linux/libs/libXaw3d-3.0-B.tar.z
and
        sunsite.unc.edu:/pub/Linux/libs/libXaw.Scrollbar.taz

For motif libs you have to pay bucks !! Read an extract that follows...
------
Metro Link, Inc. is pleased to announce the availability of OSF/Motif 1.2.2
for Linux at the introductory price of $199 for a complete runtime and
development system.

[...]

    2) Shared motif library (libXm.so.1.2.2)

[...]

This introductory offer is valid until June 10. The price will then return
to our regular Motif pricing which is $199 for runtime and $299 for
development
(which includes runtime).

You can order OSF/Motif 1.2.2 for Linux by calling Metro Link,Inc. at
(305) 970-7353 (voice) or (305) 970-7351 (fax) or by mailing us at
sa...@metrolink.com.

----------------------------------------------------------------

5) How do I build a shared DLL library for Linux ?

Ans:    You need to get the file
                /pub/linux/packages/GCC/src/tools-2.6.tar.z
        from tsx-11.mit.edu, and install it. Read the README.tr in the doc
        subdirectory thoroughly. If you find the README.tr more up to date
        than the README.ps, you will have to recreate it if you want a
        pretty Postscript version, but you *must* have groff installed. A
        `make README.ps' in the doc subdirectory should suffice.

        ** Note: the version numbers may have changed.

----------------------------------------------------------------

6) Why do I get the message "PLT__oct__FUii" when I execute a certain binary ?

Ans:    More likely than not you have a old version of the libraries, libc.so
        and/or you compiled a program using a incorrect version of `ld'.
        Solution is to get the new version of binutils package from
                tsx-11.mit.edu in /pub/linux/packages/GCC/binutils.tar.z

----------------------------------------------------------------

7) How do I build a cross compiler on platform XXX to produce code for Linux ?

Ans:    Assuming you have obtained the source code to gcc, usually you can
        just follow the instructions given in the INSTALL file for GCC.
        A `configure --target==i386-linux --host=XXX' on platform XXX
        followed by a `make' should do the trick.
        Note that you will need the linux includes, the kernel includes,
        and also to build cross assembler, and cross linker from the sources
        in /pub/linux/packages/GCC/src at tsx-11.mit.edu

----------------------------------------------------------------

8) What symbols are automatically defined by Linux's GCC ?

Ans:    Symbols defined are `linux', `__unix__', `__i386__', `__linux__',
        `__unix', `__i386', `__linux'.
        You can get a correct list by using the flag -v to gcc whilst
        compilation.

        P.s. One should note that even though the compiler automatically
        defines "linux" in a program, this is *not* POSIX compliant. Instead
        __linux__ should be used in programs that need operating-system
        specific compilation, since __linux__ *is* POSIX compliant.

        This means you can wrap your linux specific code around (for example)

        #ifdef __linux__
        ...[linux specific code here]...
        #endif /* ifdef linux */

        without adding anything extra to the Makefile defines etc..

        You can also add your own defines to the file
                /usr/lib/gcc-lib/i386-linux/2.4.0/specs

----------------------------------------------------------------

9) How do I get over BSD'isms (especially signals, sigvec etc..) when compiling code ?

Ans:    You can compile your program with -I/usr/include/bsd and link it
        with -lbsd - i.e. Add -I/usr/include/bsd to CFLAGS and -lbsd to
        the LDFLAGS line in your Makefile. Also add -D__USE_BSD_SIGNAL to
        the CFLAGS if you want BSD type signal behavior.

----------------------------------------------------------------

10) Where are SIGBUS, SIGEMT, SIGIOT, SIGTRAP, SIGSYS  etc ?

Ans:    Linux is 100% POSIX compliant and these signals are not POSIX
        signals. As an easy way out you could redefine them to SIGUNUSED.
        See the definitions in /usr/include/bsd/signal.h

        However you should note that the lack of these signals *is* compliant
        with POSIX. Instead of #define'ing to them to SIGUNUSED, new programs
        should instead say:

        #ifdef SIGSYS
        ....[non-posix sigsys code here]....
        #endif

        for code that requires the use of SIGSYS (similarly for SIGBUS).

        Here is a snippet from ISO/IEC 9945-1:1990 (IEEE Std 1003.1-1990),
...

read more »

Quote:> 13) Why are my binaries so huge and how do I reduce them ?

> Ans:       If you want smaller binaries there are a number of things you can do.
>    * Optimize the code - Use the -O6 flag when compiling,

Interesting... I've looked through GCC (admittedly not 2.4) and -O6
isn't any different from -O2 for the i386/i486.  Why is this -O6 myth
continually being propagated (yes, I know the kernel is compiled with it)?

Do we really want to make assumption about future GCC optimisations?

What if -O3 is made into a `sometimes win' optimisation and turns on
things like loop unrolling by default -- your binary isn't going to get
smaller, and it may not run faster (that is why -funroll-loops isn't
included in -O2).  You can say `it won't be' but you have no guarantee
of that -- using the highest documented optimisation must surely be the
sensible thing to do -- -O6 is *not* documented, and doesn't (currently)
do anything.

Yes, I have mentioned this numerous times before with no effect -- I
don't expect to achieve anything this time, but at least I've tried...

Follow-ups redirected to `poster' to reduce volume.

phil richards

--- a reminder ---

Code Writer:    Consult the book of Optimisation!

High Priest:    Optimisation Chapter One, verses 9 through 27:

Brother:        And Saint Attila raised the Holy Compiler up on high saying
                `Oh Lord, Bless us this Holy GCC, and with it make us
                 efficient code.'
                And the Lord did grin, and the people did feast upon the
                ANSI's and the C's, and the inline functions...

High Priest:    Skip a bit, brother.

Brother:        And then the Lord spake, saying:
                `First though shalt take out the holy -O flag.
                 Then though shalt count to two.
                 No more, no less.
                 *TWO* shall be the number of the counting, and the
                 number of the counting shall be *TWO*.
                 *THREE* shall thou not count, and neither count thou
                 one, excepting that thou then goest to two.
                 *SIX* is RIGHT OUT.  Once the number two, being the
                 second number be reached, then lobest the -O flag
                 towards thy code, which, being correct in my sight,
                 shall be as optimised as much as possible.  Amen.'

All:            Amen.

Code Writer:    Right!  (types command line)
                One!
                SIX!

Manpage Reader: Two, Sire!
---
With my deepest apologies to Monty Python...

I am assuming that my printer is configured improperly or something .. and
yes it is plugged in, turned on and connected to the  computer.

--
= FISHTANK ======== FIREPIPE ============== BOMB SHELTER BBS ========
= PO Box 75115      CiTR 101.9 fM           (604) 535-6926
= White Rock, BC    Friday nights 12:30-??  FishNet UUCP Network
= V4A 9M4           "INDUSTRIAL STRENGTH"

Quote:>I'm having problems getting Ghostscript working properly .. I finally got
>the correct X lib to make it run.  However when I feed it the line,
>"gs -sDEVICE=deskjet pwei.ps" it grabs all the fonts and says "> press
>[cr] for showpage" or whatever and then runs the interpreter.  The only
>thing is .. it never prints.
>I am assuming that my printer is configured improperly or something .. and
>yes it is plugged in, turned on and connected to the  computer.

Thanks in advance,
-Dave

--
---

I had one person reply so far telling me to use -sOutPutFile=/dev/lp1
and this didn't work at all.  I've tried wording it several different
ways on the command line aswell, and no luck.

--
= FISHTANK ======== FIREPIPE ============== BOMB SHELTER BBS ========
= PO Box 75115      CiTR 101.9 fM           (604) 535-6926
= White Rock, BC    Friday nights 12:30-??  FishNet UUCP Network
= V4A 9M4           "INDUSTRIAL STRENGTH"

Quote:(Patrick Divine) writes:

   I had one person reply so far telling me to use -sOutPutFile=/dev/lp1
   and this didn't work at all.  I've tried wording it several different
   ways on the command line aswell, and no luck.

Here is a one-line script I worked out for printing PostScript on my
HP DeskJet Plus:

cat $* | gs -q -sDEVICE=deskjet -sOutputFile=/dev/lp1 - &

Explanation:

cat $* concatenates all the files named as arguments to the shell
script.  I haven't tried this with multiple files, so I don't
know if it works to print more than one thing in the same print session.

The -q option to gs eliminates display of informational
messages.

-sDEVICE=deskjet selects the deskjet driver.  You could name a
different driver here or eliminate this option altogether and set
the environment variable GS_DEVICE to the name of the driver you
want.

You couldn't get the OutPutFile option to work because it doesn't
exist; you needed to say OutputFile instead.

In the gs man page it is documented that when gs reads from stdin
it does not produce the showpage prompts, which is why the script
is organized this way.

The gs manpage also erroneously implies that a DeskJet must have
1.5 MB of memory to print 300 dpi:

       Printing  on a Hewlett-Packard DeskJet or LaserJet at full
       resolution (300 DPI) requires a printer with at least  1.5
       Mb  of memory.  150 DPI printing requires only .5 Mb.

This is false.  A normal DeskJet will print 300 DPI with no
problems.  I believe that the limitation applies only to
non-PostScript LaserJets.
--

"Bipedalism--an unrecognized disease affecting over 99% of the population.
Symptoms include lack of traffic sense, slow rate of travel, and the
classic, easily recognized behavior known as walking."

gs -sDEVICE=deskjet "-sOutputFile=|lpr" pwei.ps

which will pipe the output to lpr. Note the quotes which are needed to
prevent the shell from grabbing and interpreting the pipe character.

Hope this helps. Took me a while to figure out.

Does anyone out there know how to send Ghostscript output to STDOUT,
other than by doing a "-sOutputFile=|cat" which introduces a redundant
process?

Regards,

Wolf
--

+-----------------+  Alcatel Austria Research Center  +43-1-391621-122 (w)
|  A L C A T E L  |  Ruthnergasse 1-7                   +43-1-391452 (fax)
+-----------------+  A-1210 Vienna-Austria/Europe        +43-1-2246913 (h)

Use the extra option -sOutputFile (watch the case of the letters!), e.g.,

        -sOutputFile=/dev/lp0           # use the device you want
or
        -sOutputFile="| some command" # to pipe the output to some command

--

--    Bull Netherlands, Professional Services, Amsterdam, The Netherlands

Thanks
--
---

You need to set the output file to a pipe into lpr, like this:

        ghostscript [options] "-sOutputFile=|lpr" filename.ps

where the entire "-sOutputFile=|lpr" argument is quoted in order to
hide the pipe character from the shell.

I know that USE.DOC talks about "setting the output device", but all
the -sDEVICE sets is the OUTPUT FORMAT. A little further down, it
says,

"Normally, output goes directly to the printer (PRN) on MS-DOS systems,
 and to a scratch file on Unix or VMS systems."

Yet a bit further down it says,

"On Unix systems, you can send the output directly to a pipe.  For
 example, to pipe the output to the command `lpr' (which, on many Unix
 systems, is the command that spools output for a printer), use the
 switch
                -sOutputFile=\|lpr
 You can also send output to stdout for piping with the switch
                -sOutputFile=-
 In this case you must also use the -q switch, to prevent Ghostscript from
 writing messages to stdout."

I prefer quoting the entire Output File argument, rather than escaping
the pipe character.

Hope this helps.

--

+-----------------+  Alcatel Austria Research Center  +43-1-391621-122 (w)
|  A L C A T E L  |  Ruthnergasse 1-7                   +43-1-391452 (fax)
+-----------------+  A-1210 Vienna-Austria/Europe        +43-1-2246913 (h)

It is better anyway, to use the pipe to lpr as OutputFile (notice
lower-case 'p'), since that will prevent different instances of
ghostscript or different users fighting over the parallel port.

All of this is explained around line 220 of use.doc which is part of
the GhostScript distribution (in $GS_LIB/doc).

--

+-----------------+  Alcatel Austria Research Center  +43-1-391621-122 (w)
|  A L C A T E L  |  Ruthnergasse 1-7                   +43-1-391452 (fax)
+-----------------+  A-1210 Vienna-Austria/Europe        +43-1-2246913 (h)

--
Brian A. Ullmark - Staff Engineer    Phone: (510) 623-5090
Amdahl Corporation - Open Systems      FAX: (510) 770-0493

Fremont, CA  94538              CompuServe: 70023,1477  

 I had this problem a day or so ago when I tried to set up Ghostscript for my
Epson LQ570. I finally got round it using :

gs -sDEVICE=epson -r60x60 -fOutputFile=/homes/rrw/wibble.out tiger.ps
cat /homes/rrw/wibble.out > /dev/lp1

[or a very similar command - I'm typing from a memory full of Modula-3 and ML
 at the moment..]

 gs -help

 Should provide a list of options from which the required modifications to the

any problems, and I'll try to clarify things.
 Incidentally, I didn't find the above in the manpage, and the suggested :

gs -sDEVICE=epson -r60x60 -fOutputFile=/ tiger.ps | lpd

 Fell over totally - the printer output the 'font found.. press <return> 'etc.
message rather than the file.
 I found the manpage for ghostview quite helpful.
 As a footnote, it might be nice if whoever maintains Ghostscript could include
a little more documentation, rather than force people to experiment until they
get it right ? [and whilst we're on the subject, what about some docs for the
-mandoc option in groff ?]

rrw.