Linux Study Notes 6. makefile file manager and makefile file creation

Linux study note 6. makefile file manager and makefile file creation-Linux general technology-Linux programming and kernel information. For details, see the following. Splitting source program files is conducive to developing large programs and improving the efficiency of programming. But the more files are separated, the more compilation and Maintenance

Difficult. To prevent changes to one or more files in a project, you do not need to recompile the entire project. Make Project

The manager is an "automatic compiler", where "automatic" refers to the ability to automatically discover updated files according to the file time and subtract

Small compilation workload. At the same time, it reads the contents of makefile to execute a lot of compilation work. You only need to write a simple

Compile the statement.
Makefile files include:
1). the target object (target) created by the make tool is required, usually the target file or executable file.
2). the object to be created depends on
3). commands to be run when creating each target body
For example, a program is designed to calculate the total and average scores of students and compile the program with the make project manager.

Step 1
Program: 1. # include
# Include "chengji. h"
Int main ()
{
Int n, I;
Float average, sum;
Scanf ("% d", & n );
Int array [n];
For (I = 0; I <= n; I ++)
{
Printf ("Please input the % dth student's score :");
Scanf ("% d", & arrary );
}
Sum = fun_sum (array, n);/* call fun_sum function */
Printf ("the all students scores is: % d", sum );
Average = fun_avg (array, n);/* call fun_avg function, return avg's value */
Printf ("the average is:", average );
}

2./* chengji. h is a head file, include the statement of fun_avg and fun_sum */
Float fun_sum (int var [], int num );
Float fun_avg (int var [], int num );

3./* fun_sum.c is fun_sum's difinition */
Float fun_sum (int var [], int num)
{
Float avrg = 0.0;
Int I;
For (I = 0; I Avrg + = var;
Return (avrg );
}

4. float fun_avg (int var [], int num)
{
Float avrg = 0.0;
Int I;
For (I = 0; I Avrg + = var;
Avrg/= num;
Return (avrg );
}

Step 2
Use the text file editor to edit the makefile file. The editing procedure is as follows:
[...] # Vi makefile1_1
2-5:2-5-main.o 2-5-fun_sum.o 2-5-fun_avg.o
Gcc 2-5-main.o 2-5-fun_sum.o 2-5-fun_avg.o-o 2-5
2-5.main.o: 2-5-main.c chengji. h
Gcc 2-5-main.c-c
2-5-fun_sum.o: 2-5-fun_sum.c
Gcc 2-5-fun_sum.c-c
2-5-fun_avg.o: 2-5-fun_avg.c
Gcc 2-5-fun_avg.c-c

Note: make
Target file: Dependent File
(Tab) command to generate the target file

Step 3
Use make to compile makefile files
[...] # Make-f makefile1_1

Step 4
If a file is modified, only the modified files will be compiled again.