gcc/g++ use

This is the compiler, doing related things.This is an open source compiler that compiles c and c++.

Procedure:

1, Preprocessing

2, Assembly

3, Link

Preprocessing

gcc -E does preprocessing and redefines an output file.

After preprocessing

gcc -E main.c -o main.i

Generate related .i files and become related things.

Compile (generate assembly)

gcc -c main.s -o main.o

Assembly generates the content of main.o file, which can be directly preprocessed into assembly.

Assembly (generates machine-identifiable code)

gcc -c main.c -o main.o

Generate .o files directly.

Link (generate executable or library)

gcc main.o -o main

Generate the main file and turn it into something corresponding.

Library

When compiling and linking, the library files are processed differently, and the static library and dynamic library are different.

Static library

Static library means that when compiling and linking, all the code of the library file is added to the executable file, so the generated file is relatively large, but the library file is no longer needed at runtime.The suffix is ​​usually ".a"

Dynamic library

The library is not placed in the executable program, and the library file is dynamically extracted during the running process.

Save space and overhead on the system, the dynamic library suffix is ​​".so".

Debugger gdb use

The use of gdb is basically related to the use of release mode.The basic things are used in the same way as debugging, but they are adjusted with simple code, not related to the previous steps.(Xcode can also perform related operations)

The relevant executable program is obtained after the gcc reaction, and then

gdb test //test executable program

1,b (break) + line number: break point

2, d (delete) + breakpoint number: delete breakpoint

3,l + line number: display code

4, s (step): statement by statement (enter function)

5, n (next): process by process

6, display && undisplay: line display or cancel normal display

7, until + line number: jump to the specified line

8, r(run): run the program

9, c (continue): from one breakpoint to the next breakpoint

10, finish: stop when the execution completes a two-digit number*!

11, j(jump) + line number: jump to the specified line

12, k (kill): terminate the program running

13,i(info) : View the value of the local variable of the current stack frame