DBX
			Home |  SCJP | SCWCD | SCEA | SCSA
				dbx is an interactive, source-level, command-line debugging tool. You can use it to run a program in a controlled manner and to inspect the state of a stopped program. dbx gives you complete control of the dynamic execution of a program, includingcollecting performance and memory usage data, monitoring memory access, and detecting memory leaks. Avalilability of dbx: http://www.sun.com/forte/cplusplus/buy.html gcore: If you want to dump core of a live process and run stack trace procedures at a later convenient time. Do the following /usr/bin/gcore [-o filename] process-id Ex: /usr/bin/gcore - pid_of_process or kill -8 pid_of_process where pid is the process id for identification. gcore creates a core image of  the specified  process.  By default, the name of the core image file will be core.process-id.  For e.g. core.11594 Change the permissions of the core file & verified it. Run the strings command on the core file.Example :  /bin/strings core.11594 | more How to run dbx on Core dbx - <executable> core How to run dbx on process dbx - pid DBX PROMPT :Before getting it to dbx prompt, it will read all the libraries i.e. .so files. Debugging a core file run the following command at dbx prompt: debug -c <full path of the core filename> <executable path of that appln> It will read the core header file Getting a stack trace from the core file write the shell script called as dbx.stacks, change permissions to executable in a  any  directory (for e.g save it as  /home/dbx.stacks). At the dbx prompt type: source /home/dbx.stacks > /home/file.pid.date How to read the stack trace? At dbx prompt, running the source on dbx.stacks, will generate the stack trace file. Open the file in vi editor, it will displays the no. of threads running Core dump error messages : Bus Error Memory Fault Segmentation Fault Floating Exception Trace/BPT Trap IOT Trap Illegal Instruction Bus Error Types of arguments and parameters don't match. I/O problems - reading past EOF, reading a closed file, bad file pointers, etc. Arrays improperly dimensioned.Ex.attempting to     - access a word starting at an odd address.     - Referencing a non-existent bus device.     - NULL or unitialized pointer, subscript out of   range. Memory Fault Subscripting arrays past the memory allocation for  your program. NULL or unitialized pointer, subscript out of range. Attempts to reference data outside valid address space Parity errors in address space Recursion (try making your own routines "read" and "write"  and then call "scanf" or "printf" and watch what happens). Segmentation Fault Subscript out of range. Handing "printf", etc. a string which is not NULL  terminated. Floating Exception Invalid floating point operation: overflow underflow divide by zero log of negative number float-to-int conversion overflow