Shulou(Shulou.com)06/03 Report--

Since the birth of the Unix system in 1969, the two great people who developed the system, Dennis Ritchie and Ken Thompson, have been figuring out how to transplant it to other machines. After several twists and turns, we finally came up with a new language on the basis of B language, which is still active on the stage and does not seem to be in decline. After rewriting the Unix kernel with C language, it is difficult to separate the relationship between C language and Unix system. So learning C under linux makes it easy to understand some of its nature, such as why C is case-sensitive, because Unix is case-sensitive.

The reason why C language can write the operating system is that it can operate memory. The most difficult and fundamental thing to learn the C language is the pointer, which operates on memory. To know how programs are stored and run in memory, you have to use the famous GDB in Unix-like systems.

Application-oriented learning, so now look at a few basic commands, and then add to the commands used. First of all, the-g parameter should be added to the program to be debugged, and the relevant debugging information should be added to the object file. For people who have used vc6.0, they always think that gdb is a command line, which is not very smooth to use, and they always doubt whether they can achieve the functions of vc6.0. When you are familiar with gdb, you will despise graphical debugging tools like vc6.0.

Gdb-Q a.out / / run a. Out a.out Q (quiet) does not print any information related to gdb.

L (list)

Format:

List

By default, the next 10 lines of the current line are listed, but to display the first 10 lines, use the-parameter. The current row is the row represented by the first line listed with list, and after it is listed, the current row is still the original row. That is, the first line listed by list is the current line after display.

Num1,num2 displays lines between num1 and num2. One of the two parameters can be empty, representing 10 lines, starting with num1 or displaying to num2. You can also specify a file name before the line. The table shows the num1 to num2 of the file. The default is the current file.

Function, showing the first 10 lines of the function function. You can also specify a file name before the function name.

* address, in addition, you can also take the address as a parameter and precede the address in the memory where the line is located with *.

If only one parameter is given, the upper and lower lines are displayed around that parameter.

Show listsize displays the number of rows currently displayed by default.

Set listsize sets the number of rows displayed by default.

To be continued.

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