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This article mainly shows you "how to debug c language under Linux". The content is simple and clear. I hope it can help you solve your doubts. Let the editor lead you to study and learn this article "how to debug c language under Linux".

Debugging is a problem that every programmer will face. How to improve the debugging efficiency of programmers and locate the problems in the program better and faster so as to speed up the progress of program development.

Debug instruction instruction:

1. Compile: gcc-o xxx xxx.c

two。 Generate a debuggable file: gcc-o xxx-g xxx.c

3. Debugger: gdb xxx

4. Execute the program:

Start starts from the first step of the program.

Run runs the program directly to the end or breakpoint

5. Set breakpoint: break line (number of lines) or function name or conditional expression

Break 6 sets a breakpoint on line 6

Break Swap sets a breakpoint at the entrance of the Swap function

Break 6 if I = = 10 set a breakpoint on line 6, requiring I = = 10

6. Delete breakpoints:

Clear deletes all breakpoints

Clear line number: delete the breakpoint of this line

Clear function name: delete the breakpoint of this function

7.info View breakpoint

8.c continue execution to the next breakpoint

9.print + variable print variable value

10.n next step

11.Q exit debugging

Example: first, we take "swapping the values of two numbers" as an example to debug. The code is as follows:

/ / We exchange the third value here to facilitate viewing the value of the variable void Swap (int* number1,int* number2) {int tmp= (* number1); (* number1) = (* number2); (* number2) = tmp;} int main () {int xdye 2; int yellow3; Swap (& x Magnetity); retrun 0;} 123456789101112131415 2. Follow the steps below to prepare for debugging:

Third, debug content (please enter instructions according to the following sequence number): ① runs the program: (gdb) run

According to the figure above, the program runs normally and exits.

② sets breakpoint: (gdb) break 12 (number of lines or function name)

③ starts debugging: (gdb) run

According to the figure above, the program starts at the breakpoint, that is, line 12.

④ print variable value: (gdb) print x (variable name)

According to the figure above, the variable x in line 11 is printed with a value of 2.

⑤ continues with the next step: (gdb) n

⑥ jumps to the next breakpoint: (gdb) c

According to the figure above, a second breakpoint is set on line 6 (the first breakpoint is on line 12), type "c" and jump directly to line 6, the second breakpoint.

⑦ continues execution until the exit function: (gdb) n

⑧ prints the value of the variable after the execution of the Swap function: (gdb) print x (gdb) print y

⑨ exit debugging: (gdb) Q

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