Top - Frequently Asked Questions

This FAQ is broken out in to several topics.


  1. "Where do I get the latest version of top?"
    The latest version of top is now available at the site "" in the directory "/pub/top". It is also available at "" in the directory "/pub/top".

  2. "Is there a web page for top?"
    Not at this time, but I am planning one. When it is finally available, you will be able to find it at ""

  3. "Is there a mailing list for top?"
    Currently there is a top developers mailing list that is used by beta testers and other people who help me port the program to various machines. I am planning a general mailing list for announcements and such, but it is not yet available.

  4. "How can I find out when all these things become available?"
    Information about the web site and the mailing list will be made available in future distributions of top. New distributions will be announced on the appropriate Usenet newsgroups (including comp.sources.unix).

  5. "Why does it take so long for a new version of top to go through the beta test process?"
    This is completely my fault. I have just not had the time recently to give top the attention it deserves. I thank everyone for their patience, and I hope that with the recent changes in the direction of my career that I can spend more time on this.

  6. "Top is not written in ANSI C. Do you ever plan to change that?"
    Top predates ANSI C by about 5 years. Yeah, it'll get "fixed" eventually. Probably in 3.5.


  7. "Configure said that it saw /proc and is recommending that I install top setuid root. Is there any way around this? Is it safe?"
    There is no way around it. Complain to POSIX. Every effort has been made to make top a secure setuid program. However, we cannot guarantee that there are no security problems associated with this configuration. The places where top is most vulnerable are the builtin kill and renice commands. There is no internal top command that causes top to start a shell as a subprocess. Some SVR4 systems may contain a bug that enables a user to renice his own processes downward (to lower nice values that are more favorable for the process). This problem has been fixed for the Solaris 2.x modules, but may still exist in others. We will hopefully fix this up in the next release.

  8. "Why is Configure a c-shell script? I thought c-shell scripts were evil?"
    They are. :-) I'll probably be rewriting the Configure script for the next release.


  9. "We just upgraded our operating system to a new version and top broke. What should we do?"
    Recompile it. Top is very sensitive to changes in internal kernel data structures. It is not uncommon for a new version of the operating system to include changes to kernel data structures.


  10. "I just finished compiling top and it works fine for root, but when I try to run it as a regular user it either complains about files it can't open or it doesn't display all the information it should. Did I do something wrong?"
    Well, you're just not done. On many operating systems today, access to many of the kernel memory devices and other system files is restricted to either root or a particular group. The Configure script figures this out (usually) and makes sure that the "intsall" rule in the Makefile will install top so that anyone can run it successfully. However, you have to *install* it first. Do this with the command "make install".

  11. "Top is (not) displaying idle processes and I don't (do) want it to."
    This default has only changed about a dozen times, and I finally got tired of people whining about it. Go read the manual page for the current version and pay special attention to the description of the "TOP" environment variable.

  12. "We have so much memory in our machine that the memory status display (the fourth line) ends up being longer than 80 characters. This completely messes up top's output. Is there a patch?"
    Most modules have been changed to use new memory formatting functions which will display large values in terms of megabytes instead of kilobytes. This should fix all occurences of this problem. If you encounter a system where this large memory display overflow is still occurring, please let me know (send mail to ). Also note that newer versions of top can use columns beyond 79, and understand window resizes. So you can always make your window bigger.

  13. "I tried to compile top with gcc and it doesn't work. I get compilation errors in the include files, or I get an executable that dumps core, or top displays incorrect numbers in some of the displays. What's wrong?"
    Gnu CC likes very much to use its own include files. Not being a gcc expert, I can't explain why it does this. But I can tell you that if you upgrade your operating system (say from Solaris 2.4 to Solaris 2.5) after installing gcc, then the include files that gcc uses will be incorrect, especially those found in the "sys" directory. Your choices are: (1) rebuild and reinstall the "standard" include files for gcc (look for scripts in the distribution called "fixincludes" and "fixing.svr4"), (2) compile machine.c with "CFLAGS=-I/usr/include" then make the rest of the object files normally, or (3) use "cc". Solaris 2.6 users should also consult
    FAQ #20.

  14. "The cpu state percentages are all wrong, indicating that my machine is using 95% system time when it is clearly idle. What's wrong?"
    This can happen if you compiled with gcc using the wrong include files. See the previous question.


  15. "I tried compiling top under SunOS version 4.1.x and it got compile time errors. Is there a patch?"
    If you try compiling top in a "System V environment" under SunOS (that is, /usr/5bin is before /usr/bin on your path) then the compilation may fail. This is mostly due to the fact that top thinks its being compiled on a System V machine when it really isn't. The only solution is to put /usr/bin and /usr/ucb before /usr/5bin on your path and try again. SVR4-derived PROBLEMS

  16. "When I run top on my SVR4-derived operating system, it displays all the system information at the top but does not display any process information (or only displayes process information for my own processes). Yet when I run it as root, everything works fine."
    Your system probably uses the pseudo file system "/proc", which is by default only accessible by root. Top needs to be installed setuid root on such systems if it is going to function correctly for normal users.


  17. "Under Solaris 2, when I run top as root it only shows root processes, or it only shows processes with a PID less than 1000. It refuses to show anything else. What do I do?"
    You probably compiled it with /usr/ucb/cc instead of the real C compiler. /usr/ucb/cc is a cc front end that compiles programs in BSD source-level compatability mode. You do not want that. Make sure that /usr/ucb is not on your path and try compiling top again.

  18. "Under Solaris 2, I compiled top using what I am sure is the correct compiler but when I try to run it it complains about missing dynamic libraries. What is wrong?"
    Check to see if you have LD_LIBRARY_PATH defined in your shell. If you do, make sure that /usr/ucblib is not on the path anywhere. Then try compiling top again.

  19. "Under Solaris 2, when I try to run top it complains that it can't open the library "". So I changed the LIBS line in m_sunos5.c to include -R/usr/ucblib to make sure that the dynamic linker will look there when top runs. I figured this was just an oversight. Was I right?"
    No, you were not right. As distributed, top requires NO alterations for successful compilation and operations under Solaris 2.0, 2.1, 2.2, 2.3, 2.4, and 2.5. You probably compiled top with /usr/ucb/cc instead of the real C compiler. See
    FAQ #10 for more details.

  20. "When I try to compile top under Solaris 2.6 using gcc I get compile time errors. There appear to be problems with the include files, such as 'u_rlimit has incomplete type' and/or 'u_saved_rlimit has incomplete type'. I've already run fixinc.svr4 as per FAQ #13. Why didn't that fix it?"
    Only top versions 3.5 and later are compatible with Solaris 2.6. In addition, there is a bug in gcc 2.7.2.x with the fixinc.svr4 script. The patch is included in the top distribution as the file "gcc-" and is also available from the top web site ("/top"). See the Solaris FAQ for more details ("").


  21. "When I try to run Configure, it complains about a syntax error."
    Some versions of SCO's csh do not understand the syntax "$<". This breaks Configure. You'll just have to hack around it for now: the Configure script is going to be completely redone in the near future anyway.


  22. "The load average and memory displays don't work right. Why?"
    This is a known bug with the svr42 module. The problem has been traced down to a potential bug in the "mem" driver. The author of the svr42 module is working on a fix.


  23. I'm still stuck. To whom do I report problems with top?"
    The most common problems are caused by top's sensitivity to internal kernel data structures. So make sure that you are using the right include files, and make sure that you test out top on the same machine where you compiled it. Sun's BSD Source Compatability Mode is also a common culprit. Make sure you aren't using either /usr/ucb/cc or any of the libraries in /usr/ucblib. Finally, make sure you are using the correct module. If there does not appear to be one appropriate for your computer, then top probably will not work on your system. If after reading all of this file and checking everything you can you are still stuck, then send mail to "". I will answer your mail when I have time. Please bear with me in that regard! If it looks like the problem is machine-specific, I will forward the report along to the module's author. If you would like to converse directly with the module author, the authors' names are listed at the beginning of the module .c file in the "machine" directory.
    Last updated: Tue Nov 18 22:48:26 EST 1997