Gdb Error Codes
Contents |
option >g++ -g -o gdbprog gdbprog.cc Load executable into gdb >gdb gdbprog GDB is free software and you are welcome to distribute copies of it under certain conditions; type "show copying" to see the gdb where command conditions. There is absolutely no warranty for GDB; type "show warranty" for details. GDB
Gdb Reload Executable
4.12 (sparc-sun-sunos4.1.3C), Copyright 1994 Free Software Foundation, Inc... Use help to get information about available commands. Run program with run command (gdb)
Gdb Restart Program
run Starting program: gdbprog Program received signal SIGSEGV, Segmentation fault. 0x2350 in DoOperation (ptrs=0x18bc0) at gdbprog.cc:24 24 sum += *ptrs[i]; Program will run until termination, a break point is reached, or an error occurs You can
Gdb Tutorial
find out where the program is, i.e. where the segmentation fault occurred, using the where command. This gives a function call trace of how you got to this point and shows line numbers inside files. (gdb) where #0 0x2350 in DoOperation (ptrs=0x18bc0) at gdbprog.cc:24 #1 0x24b0 in main () at gdbprog.cc:45 list shows surrounding code (gdb) list 19 { 20 int sum = 0; 21 int i; 22 23 for(i = 0;i how to use gdb < 10;i++) 24 sum += *ptrs[i]; 25 } 26 27 28 void PrintArray() print allows you to display variables or any language expression. You may need a cast to display value correctly. (gdb) print i $1 = 1 (gdb) print ptrs[i] $2 = (int *) 0x0 (gdb) print (int* [10])*ptrs $3 = {0x18be8, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0} break sets breakpoints at places where you want the debugger to stop. break function-name will set a breakpoint at the start of the function. You can set multiple breakpoints. (gdb) break InitArrays Breakpoint 1 at 0x2298: file gdbprog.cc, line 10. run will restart the program when stopped in mid-execution (gdb) run The program being debugged has been started already. Start it from the beginning? (y or n) y Starting program: gdbprog Breakpoint 1, InitArrays (array=0x18be8) at gdbprog.cc:10 10 for(i = 0;i < 1;i++) The program stops before executing the statement where the break is set. step executes one instruction. It will step into functions. (gdb) step 12 ptrArray[i] = array + i; (gdb) print i $4 = 0 (gdb) step 13 iArray[i] = i; (gdb) step 14 } (gdb) step 15 } (gdb) step main () at gdbprog.cc:45 45 cout << "operation result is " << DoOperation(ptrArray) << '\n'; After changing program,
granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later gdb source code version published by the Free Software Foundation; with the Invariant Sections gdb rerun program being “Free Software” and “Free Software Needs Free Documentation”, with the Front-Cover Texts being “A GNU gdb breakpoint commands example Manual,” and with the Back-Cover Texts as in (a) below. (a) The FSF's Back-Cover Text is: “You are free to copy and modify this GNU Manual. Buying copies https://www.cs.rochester.edu/~nelson/courses/csc_173/review/gdb.html from GNU Press supports the FSF in developing GNU and promoting software freedom.” Next:Summary, Previous:(dir), Up:(dir) Debugging with gdb This file describes gdb, the gnu symbolic debugger. This is the Tenth Edition, for gdb (GDB) Version 7.12.50.20161019-git. Copyright (C) 1988-2016 Free Software Foundation, Inc. This edition of the GDB manual is dedicated to the memory https://www.sourceware.org/gdb/current/onlinedocs/gdb.html of Fred Fish. Fred was a long-standing contributor to GDB and to Free software in general. We will miss him. Summary: Summary of gdb Sample Session: A sample gdb session Invocation: Getting in and out of gdb Commands: gdb commands Running: Running programs under gdb Stopping: Stopping and continuing Reverse Execution: Running programs backward Process Record and Replay: Recording inferior's execution and replaying it Stack: Examining the stack Source: Examining source files Data: Examining data Optimized Code: Debugging optimized code Macros: Preprocessor Macros Tracepoints: Debugging remote targets non-intrusively Overlays: Debugging programs that use overlays Languages: Using gdb with different languages Symbols: Examining the symbol table Altering: Altering execution GDB Files: gdb files Targets: Specifying a debugging target Remote Debugging: Debugging remote programs Configurations: Configuration-specific information Controlling GDB: Controlling gdb Extending GDB: Extending gdb Interpreters: Command Interpreters TUI: gdb Text User Interface Emacs: Using gdb under gnu Emacs GDB/MI: gdb's Machine Interface. Annotations: gdb's annotation interface. JIT Interface: Using the JIT debugging interface. In-Proces
Project debugger, allows you to see what is going on `inside' another program while it executes -- or what another program was doing at the moment it crashed. GDB can do https://www.gnu.org/s/gdb/ four main kinds of things (plus other things in support of these) to http://cs.baylor.edu/~donahoo/tools/gdb/tutorial.html help you catch bugs in the act: Start your program, specifying anything that might affect its behavior. Make your program stop on specified conditions. Examine what has happened, when your program has stopped. Change things in your program, so you can experiment with correcting the effects of one bug and gdb error go on to learn about another. The program being debugged can be written in Ada, C, C++, Objective-C, Pascal (and many other languages). Those programs might be executing on the same machine as GDB (native) or on another machine (remote). GDB can run on most popular UNIX and Microsoft Windows variants. GDB version 7.12 Version 7.12 of GDB, the GNU Debugger, is now available gdb error codes for download. See the ANNOUNCEMENT for details including changes in this release. An errata list (PROBLEMS) and documentation are also available. News October 7th, 2016: GDB 7.12 Released! The latest version of GDB, version 7.12, is available for download. Changes in this release include: New target support: Andes NDS32 (nds32*-*-elf) Rust: Debugging programs written in Rust is now supported. Fortran: Support structures with fields of dynamic types and arrays of dynamic types. Various Python enhancements (new convenience functions, enhanced support for breakpoints). Various GDBserver enhancements: btrace recording without maintaining an active GDB connection. tracepoints and fast tracepoints support added on s390-linux, s390x-linux, powerpc64-linux, and powerpc64le-linux. Support for the following remote target protocols and ROM monitors has been removed: target m32rsdi (Remote M32R debugging over SDI) target mips (MIPS remote debugging protocol) target pmon (PMON ROM monitor) target ddb (NEC's DDB variant of PMON for Vr4300) target rockhopper (NEC RockHopper variant of PMON) target lsi (LSI variant of PMO) See the NEWS file for a more complete and detailed list of what this release includes. Aug 1st, 2016: GDB 7.12 branch created The GDB 7.12 branch (gdb-7.12-branch) has
summation of (X^0)/0! + (X^1)/1! + (X^2)/2! + (X^3)/3! + (X^4)/4! + ... + (X^n)/n!, given x and n as inputs. However the program outputs a value of infinity, regardless of the inputs. We will take you step by step through the debugging process and trace the errors: Download the sample program broken.cpp Compile the program and execute the program. % g++ -g broken.cpp -o broken % ./broken Whatever the input, the output will be inf. The -g option is important because it enables meaningful GDB debugging. Start the debugger % gdb broken This only starts the debugger; it does not start running the program in the debugger. Look at the source code and set a breakpoint at line 43 (gdb) b 43 which is double seriesValue = ComputeSeriesValue(x, n); Now, we start to run the program in the debugger. (gdb) run Note: If you need to supply the command-line arguments for the execution of the program, simply include them after the run command, just as normally done on the command line. The program starts running and asks us for the input. Let's enter the values as x=2 and n=3. The expected output value is 5. The following is a snapshot of the program running in the debugger: This program is used to compute the value of the following series : (x^0)/0! + (x^1)/1! + (x^2)/2! + (x^3)/3! + (x^4)/4! + ........ + (x^n)/n! Please enter the value of x : 2 Please enter an integer value for n : 3 Breakpoint 1, main () at broken.cpp:43 43 double seriesValue = ComputeSeriesValue(x, n); Note that the program execution stopped at our first (and only) breakpoint. Step into the ComputeSeriesValue() function To step into a function call, we use the following command: (gdb) step ComputeSeriesValue (x=2, n=3) at broken.cpp:17 17 double seriesValue=0.0; At this point, the program control is at the first statement of the function ComputeSeriesValue (x=2, n=3) Next let's step through the program until we get into ComputeFactorial. (gdb) next 18 double xpow=1; (gdb) n 20 for (int k = 0; k <= n; k++) { (gdb) 21 seriesValue += xpow / ComputeFactorial(k) ; (gdb) s ComputeFactorial (number=0) at broken.cpp:7 7 int fact=0; Here we use the next command, which is similar to step except it will step over (instead of into) functions. The distinction doesn't matter here since there are no functions. You may use the shortest, unambigious spelling of a GDB command to save some typing. Here we use n and s instead of next and step, respectively. If t