<>1. The process of generating an executable program
stay C/CPP in , Generating executable programs requires preprocessing , compile , assembly , Link four processes
<>1.1 Pretreatment
Pretreatment stage ：
* Expand header file , Macro replacement , Conditional compilation , Remove comments
* generate .i file
<>1.2 compile
* Check syntax
* Generate assembly code
* generate .s file
<>1.3 assembly
Assembly phase :
* Convert assembly code into binary machine code
* Generate a symbol table for this file
* generate .o file
<>1.4 link
link ：
* Consolidated segment table
* Summary symbol table , Find the address of the calling function , Link correspondence , Merge together
* Put all .o Files and static libraries , Dynamic libraries are linked together to generate executable programs
<>2.CPP Treatment of
Why? cpp Function overloading is not supported c Language does not support function overloading ?
Through the generation process of executable files, we know , We know that in the compilation process , The mapping relationship between function name and function address will be recorded in the symbol table .
// Take the following simple program as an example void f(int a,double b) { printf("%d %f",a,b); } void f(double b,
int a) { printf("%f %d",b,a); }
View the symbol table corresponding to the function
It can be concluded that cpp The function name in the assembly is ：
Z Function name length Function name Parameter type initials 1, Initials 2…
<>3.C Language processing
// Take the following procedure as an example void f(int a,int b) { printf("%d %d",a,b); } void func(int c,int d)
{ printf("%d %d",c,d); }
View symbol table
C In language symbol table , The address of the function also corresponds to the function name , however C The function name of the symbol table in the language does not contain parameter types , Function name length information .
This also explains C Why doesn't the language support function overloading . Because when the same function name is defined , An error occurred while summarizing the symbol table . So this kind of error occurs in the assembly stage
<>4.CPP Type of function overload
In symbol table , Function name and address correspond one by one . and CPP The function name in the symbol table is ：Z Function name length Function name Parameter type initials 1, Initials 2…
So the types of function overloading are ：
* Parameters of function ; Different types
* The order of function parameters is different
* The number of function parameters is different
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