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• Dev C Running Argc Argv Debugger Free
• Dev C Running Argc Argv Debugger List

Running eg1.c with ‘run’ gdb will break when “value” equals “div”, avoiding having to ‘continue’ manually until they are equal. Breakpoint conditions can be any valid C expression when debugging C programs, indeed any valid expression in the language your program is using. Although I do like using Dev-C I wish it wasn't discontinued because it does have some annoying bugs. For examlple, int the past I have written a program, comipled it, written another program and when i've gone to compiler it it opens the previous program:S ODD!

The GNU Debugger (GDB) is a portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada, C, C++, Objective-C, Free Pascal, Fortran, Go,^[2] and partially others.^[3]

History[edit]

GDB was first written by Richard Stallman in 1986 as part of his GNU system, after his GNU Emacs was 'reasonably stable'.^[4] GDB is free software released under the GNU General Public License (GPL). It was modeled after the DBX debugger, which came with Berkeley Unix distributions.^[4]

From 1990 to 1993 it was maintained by John Gilmore.^{[citation needed]} Now it is maintained by the GDB Steering Committee which is appointed by the Free Software Foundation.^[5]

Technical details[edit]

Features[edit]

GDB offers extensive facilities for tracing and altering the execution of computer programs. The user can monitor and modify the values of programs' internal variables, and even call functions independently of the program's normal behavior.

GDB target processors (as of 2003) include: Alpha, ARM, AVR, H8/300, Altera Nios/Nios II, System/370, System 390, X86 and its 64-bit extension X86-64, IA-64 'Itanium', Motorola 68000, MIPS, PA-RISC, PowerPC, SuperH, SPARC, and VAX. Lesser-known target processors supported in the standard release have included A29K, ARC, ETRAX CRIS, D10V, D30V, FR-30, FR-V, Intel i960, 68HC11, Motorola 88000, MCORE, MN10200, MN10300, NS32K, Stormy16, and Z8000. (Newer releases will likely not support some of these.) GDB has compiled-in simulators for even lesser-known target processors such like M32R or V850.^[6]

GDB is still actively developed. As of version 7.0 new features include support for Python scripting^[7] and as of version 7.8 GNU Guile scripting as well.^[8] Since version 7.0, support for 'reversible debugging' — allowing a debugging session to step backward, much like rewinding a crashed program to see what happened — is available.^[9]

Remote debugging[edit]

GDB offers a 'remote' mode often used when debugging embedded systems. Remote operation is when GDB runs on one machine and the program being debugged runs on another. GDB can communicate to the remote 'stub' that understands GDB protocol through a serial device or TCP/IP.^[10] A stub program can be created by linking to the appropriate stub files provided with GDB, which implement the target side of the communication protocol.^[11] Alternatively, gdbserver can be used to remotely debug the program without needing to change it in any way.

The same mode is also used by KGDB for debugging a running Linux kernel on the source level with gdb. With KGDB, kernel developers can debug a kernel in much the same way as they debug application programs. It makes it possible to place breakpoints in kernel code, step through the code, and observe variables. On architectures where hardware debugging registers are available, watchpoints can be set which trigger breakpoints when specified memory addresses are executed or accessed. KGDB requires an additional machine which is connected to the machine to be debugged using a serial cable or Ethernet. On FreeBSD, it is also possible to debug using Firewiredirect memory access (DMA).^[12]

Graphical user interface[edit]

The debugger does not contain its own graphical user interface, and defaults to a command-line interface. Several front-ends have been built for it, such as UltraGDB, Xxgdb, Data Display Debugger (DDD), Nemiver, KDbg, the Xcode debugger, GDBtk/Insight, and HP Wildebeest Debugger GUI (WDB GUI). IDEs such as Codelite, Code::Blocks, Dev-C++, Geany, GNAT Programming Studio (GPS), KDevelop, Qt Creator, Lazarus, MonoDevelop, Eclipse, NetBeans, and Visual Studio can interface with GDB. GNU Emacs has a 'GUD mode' and tools for VIM exist (e.g. clewn). These offer facilities similar to debuggers found in IDEs.

Some other debugging tools have been designed to work with GDB, such as memory leak detectors.

Examples of commands[edit]

An example session[edit]

Consider the following source-code written in C:

Using the GCC compiler on Linux, the code above must be compiled using the -g flag in order to include appropriate debug information on the binary generated, thus making it possible to inspect it using GDB. Assuming that the file containing the code above is named example.c, the command for the compilation could be:

And the binary can now be run:

Since the example code, when executed, generates a segmentation fault, GDB can be used to inspect the problem.

The problem is present in line 8, and occurs when calling the function strlen (because its argument, s, is NULL).Depending on the implementation of strlen (inline or not), the output can be different, e.g.:

It can give fine tuning control from fractions of a semi-tone to huge multi-octave pitch swings. Pitchwheel (64-Bit) plug-in freely alters the pitch and timbre of a sound in real-time. It features MIDI controllable with multi-octave adjustments, and fine wheel detuning, eight note chords for creating easy vocal harmonies and effects, unique inertia settings for springy vibrato effects, and wild pitch swings, and ideal for experimental and live performances. It has a large, easy to use dials and simple parameters making it a fast and creative effect unit.

To fix the problem, the variable a (in the function main) must contain a valid string. Here is a fixed version of the code:

Recompiling and running the executable again inside GDB now gives a correct result:

GDB prints the output of printf in the screen, and then informs the user that the program exited normally.

See also[edit]

• Binary File Descriptor library (libbfd)
• DDD, a GUI for GDB and other debuggers

References[edit]

1. ^Brobecker, Joel (2020-02-08). 'GDB 9.1 released!'. Retrieved 2020-02-09.
2. ^'GDB Documentation - Supported Languages'. Retrieved 2011-11-28.
3. ^'GDB Documentation - Summary'. Retrieved 2011-11-28.
4. ^ ^ab'Richard Stallman lecture at the Royal Institute of Technology, Sweden (1986-10-30)'. Retrieved 2006-09-21. Then after GNU Emacs was reasonably stable, which took all in all about a year and a half, I started getting back to other parts of the system. I developed a debugger which I called GDB which is a symbolic debugger for C code, which recently entered distribution. Now this debugger is to a large extent in the spirit of DBX, which is a debugger that comes with Berkeley Unix.
5. ^'GDB Steering Committee'. Retrieved 2008-05-11.
6. ^'GDB Documentation - Summary - Contributors'. Retrieved 2011-12-01.
7. ^'GDB 7.0 Release Notes'. Retrieved 2011-11-28.
8. ^Joel Brobecker (2014-07-29). 'GDB 7.8 released!'. Retrieved 2014-07-30.
9. ^'Reverse Debugging with GDB'. Retrieved 2014-01-20.
10. ^'Howto: GDB Remote Serial Protocol: Writing a RSP Server'(PDF).
11. ^'Implementing a remote stub'.
12. ^'Kernel debugging with Dcons'.

External links[edit]

Documentation[edit]

• Richard M. Stallman, Roland Pesch, Stan Shebs, et al., Debugging with GDB (Free Software Foundation, 2011) ISBN978-0-9831592-3-0

Tutorials[edit]

• RMS's gdb Tutorial (Ryan Michael Schmidt, not Richard Matthew Stallman)

The GNU Debugger (GDB) is a portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada, C, C++, Objective-C, Free Pascal, Fortran, Go,^[2] and partially others.^[3]

History[edit]

GDB was first written by Richard Stallman in 1986 as part of his GNU system, after his GNU Emacs was 'reasonably stable'.^[4] GDB is free software released under the GNU General Public License (GPL). It was modeled after the DBX debugger, which came with Berkeley Unix distributions.^[4]

Dev C Running Argc Argv Debugger Free

From 1990 to 1993 it was maintained by John Gilmore.^{[citation needed]} Now it is maintained by the GDB Steering Committee which is appointed by the Free Software Foundation.^[5]

Technical details[edit]

Features[edit]

GDB offers extensive facilities for tracing and altering the execution of computer programs. The user can monitor and modify the values of programs' internal variables, and even call functions independently of the program's normal behavior.

GDB target processors (as of 2003) include: Alpha, ARM, AVR, H8/300, Altera Nios/Nios II, System/370, System 390, X86 and its 64-bit extension X86-64, IA-64 'Itanium', Motorola 68000, MIPS, PA-RISC, PowerPC, SuperH, SPARC, and VAX. Lesser-known target processors supported in the standard release have included A29K, ARC, ETRAX CRIS, D10V, D30V, FR-30, FR-V, Intel i960, 68HC11, Motorola 88000, MCORE, MN10200, MN10300, NS32K, Stormy16, and Z8000. (Newer releases will likely not support some of these.) GDB has compiled-in simulators for even lesser-known target processors such like M32R or V850.^[6]

GDB is still actively developed. As of version 7.0 new features include support for Python scripting^[7] and as of version 7.8 GNU Guile scripting as well.^[8] Since version 7.0, support for 'reversible debugging' — allowing a debugging session to step backward, much like rewinding a crashed program to see what happened — is available.^[9]

Remote debugging[edit]

GDB offers a 'remote' mode often used when debugging embedded systems. Remote operation is when GDB runs on one machine and the program being debugged runs on another. GDB can communicate to the remote 'stub' that understands GDB protocol through a serial device or TCP/IP.^[10] A stub program can be created by linking to the appropriate stub files provided with GDB, which implement the target side of the communication protocol.^[11] Alternatively, gdbserver can be used to remotely debug the program without needing to change it in any way.

The same mode is also used by KGDB for debugging a running Linux kernel on the source level with gdb. With KGDB, kernel developers can debug a kernel in much the same way as they debug application programs. It makes it possible to place breakpoints in kernel code, step through the code, and observe variables. On architectures where hardware debugging registers are available, watchpoints can be set which trigger breakpoints when specified memory addresses are executed or accessed. KGDB requires an additional machine which is connected to the machine to be debugged using a serial cable or Ethernet. On FreeBSD, it is also possible to debug using Firewiredirect memory access (DMA).^[12]

Graphical user interface[edit]

The debugger does not contain its own graphical user interface, and defaults to a command-line interface. Several front-ends have been built for it, such as UltraGDB, Xxgdb, Data Display Debugger (DDD), Nemiver, KDbg, the Xcode debugger, GDBtk/Insight, and HP Wildebeest Debugger GUI (WDB GUI). IDEs such as Codelite, Code::Blocks, Dev-C++, Geany, GNAT Programming Studio (GPS), KDevelop, Qt Creator, Lazarus, MonoDevelop, Eclipse, NetBeans, and Visual Studio can interface with GDB. GNU Emacs has a 'GUD mode' and tools for VIM exist (e.g. clewn). These offer facilities similar to debuggers found in IDEs.

Some other debugging tools have been designed to work with GDB, such as memory leak detectors.

Examples of commands[edit]

An example session[edit]

Consider the following source-code written in C:

Using the GCC compiler on Linux, the code above must be compiled using the -g flag in order to include appropriate debug information on the binary generated, thus making it possible to inspect it using GDB. Assuming that the file containing the code above is named example.c, the command for the compilation could be:

And the binary can now be run:

Since the example code, when executed, generates a segmentation fault, GDB can be used to inspect the problem.

The problem is present in line 8, and occurs when calling the function strlen (because its argument, s, is NULL).Depending on the implementation of strlen (inline or not), the output can be different, e.g.:

To fix the problem, the variable a (in the function main) must contain a valid string. Here is a fixed version of the code:

Recompiling and running the executable again inside GDB now gives a correct result:

Dev C Running Argc Argv Debugger List

GDB prints the output of printf in the screen, and then informs the user that the program exited normally.

See also[edit]

• Binary File Descriptor library (libbfd)
• DDD, a GUI for GDB and other debuggers

References[edit]

1. ^Brobecker, Joel (2020-02-08). 'GDB 9.1 released!'. Retrieved 2020-02-09.
2. ^'GDB Documentation - Supported Languages'. Retrieved 2011-11-28.
3. ^'GDB Documentation - Summary'. Retrieved 2011-11-28.
4. ^ ^ab'Richard Stallman lecture at the Royal Institute of Technology, Sweden (1986-10-30)'. Retrieved 2006-09-21. Then after GNU Emacs was reasonably stable, which took all in all about a year and a half, I started getting back to other parts of the system. I developed a debugger which I called GDB which is a symbolic debugger for C code, which recently entered distribution. Now this debugger is to a large extent in the spirit of DBX, which is a debugger that comes with Berkeley Unix.
5. ^'GDB Steering Committee'. Retrieved 2008-05-11.
6. ^'GDB Documentation - Summary - Contributors'. Retrieved 2011-12-01.
7. ^'GDB 7.0 Release Notes'. Retrieved 2011-11-28.
8. ^Joel Brobecker (2014-07-29). 'GDB 7.8 released!'. Retrieved 2014-07-30.
9. ^'Reverse Debugging with GDB'. Retrieved 2014-01-20.
10. ^'Howto: GDB Remote Serial Protocol: Writing a RSP Server'(PDF).
11. ^'Implementing a remote stub'.
12. ^'Kernel debugging with Dcons'.

External links[edit]

Documentation[edit]

• Richard M. Stallman, Roland Pesch, Stan Shebs, et al., Debugging with GDB (Free Software Foundation, 2011) ISBN978-0-9831592-3-0

Tutorials[edit]

• RMS's gdb Tutorial (Ryan Michael Schmidt, not Richard Matthew Stallman)