What is a program crash in comparison?


When running a user program, you might see a message that alerts you to a condition and then announces "core dumped." A program that contains a bug in it might never fail, might stomp on good data, might generate faulty results, or might result in a core dump. It all depends on the nature of the bug in the program.

When the message "core dumped" is displayed, you will usually find a file called core in the directory from which the program was executed. This file contains information about the program, allowing the programmer to debug the program and locate the source of trouble. To anyone but the programmer, core files are generally not of interest and just eat up disk space. C shell users can use the limit command to prevent core files from being left behind, as shown below.

Figure 1-2 Limiting the core dump file size in the C shell
 Hiya 3:  limit  cputime         unlimited  filesize        unlimited  datasize        2097148 kbytes  stacksize       8192 kbytes  coredumpsize    unlimited  descriptors     64  memorysize      unlimited  Hiya 4:  limit coredumpsize 1 megabyte  Hiya 5:  limit  cputime         unlimited  filesize        unlimited  datasize        2097148 kbytes  stacksize       8192 kbytes  coredumpsize    1024 kbytes  descriptors     64  memorysize      unlimited  Hiya 6: 

In this example, the user has limited the size of program core dumps to one megabyte.

Program core dumps and their core files are not to be confused with system crash dumps and their savecore files. A thousand users can all be crashing their own programs and the system will still be running like a champ and your data will still be safe well, unless you are running one of the buggy programs!



PANIC. UNIX System Crash Dump Analysis Handbook
PANIC! UNIX System Crash Dump Analysis Handbook (Bk/CD-ROM)
ISBN: 0131493868
EAN: 2147483647
Year: 1994
Pages: 289
Authors: Chris Drake

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