Use the same system call using the Library function API and the embed assembly code in C code two ways

Zhu Hengzhi + "Linux kernel analysis" MOOC course http://mooc.study.163.com/course/USTC-1000029000 "

Use the same system call using the Library function API and the embed assembly code in C code two ways

List of system calls see HTTP://CODELAB.SHIYANLOU.COM/XREF/LINUX-3.18.6/ARCH/X86/SYSCALLS/SYSCALL_32.TBL

I have chosen number 20th:

Use the Library function API to display the ID of the process on the screen:

Use the C language to embed the assembly code:

Code:

#include <unistd.h>

#include <stdio.h>

int main ()

{

pid_t pid; PID = Getpid ();

ASM volatile (

"Mov $0x14,%%eax\n\t"

"Int $0x80\n\t"

"Mov%%eax,%0\n\t"

< Span class= "Hljs-keyword" >&NBSP;: "=m" (PID));

< Span class= "Hljs-keyword" > printf ( "pid =%d \ n", pid);

< Span class= "Hljs-keyword" > return 0;

< Span class= "Hljs-keyword" > }

Use the same system call using the Library function API and the embed assembly code in C code two ways