I am Learning English language can open the fullPath via opendir(“Full Path ”) returns dir* value then another readdir(“dir* ”) return value biz popkalar ichidagi

I am Learning English language

can open the fullPath via OPENDIR(“Full Path ”)

returns DIR* value

then another READDIR(“DIR* ”) return value

biz popkalar ichidagi fayllarni o’qish uchun quyidagi funcsiyalardan foydalanamiz

opendir funksiyasi bilan ochamiz keyin READDIR funksiyasi bilan uni ichidagi file lar nomlarini olamiz.

Programmani ishlatganda kiruvchi va chiquvchi fayllarni berib yuborish uchun quyidagicha amalga oshiriladi :

./a.out < infile > outfile

< bu simvol bilan kiruvchi narsalar ko’rsatiladi.

> bu bilan natijaning chiqish yo’li ko’rsatiladi.

then the file named infile will be copied to the file named outfile.

Figure 1.4. List all the files in a directory

#include

#include

#include

#define BUFFSIZE 4096

int

main(void)

{

int n;

char buf[BUFFSIZE];
while ((n = read(STDIN_FILENO, buf, BUFFSIZE)) > 0)

if (write(STDOUT_FILENO, buf, n) != n)

err_sys("write error");

if (n < 0)

err_sys("read error");
exit(0);

}

PROCESES

Proceses bilan ishlashda asosan 3 ta yopiq funksiyladan foydalaniladi misol uchun

GETPID() return value =pid_t variable ishlayotgan proces ID ni qaytaradi

Fork() bu funksiya process ID larni birma bir qaytaradi

Exec

waitpid

misol uchun:

#include "apue.h"

#include
int

main(void)

{

char buf[MAXLINE]; /* from apue.h */

pid_t pid;

int status;

printf("%% "); /* print prompt (printf requires %% to print %) */

while (fgets(buf, MAXLINE, stdin) != NULL) {

if (buf[strlen(buf) - 1] == "\n")

buf[strlen(buf) - 1] = 0; /* replace newline with null */

if ((pid = fork()) < 0) {

err_sys("fork error");

} else if (pid == 0) { /* child */

execlp(buf, buf, (char *)0);

err_ret("couldn't execute: %s", buf);

exit(127);

}
/* parent */

if ((pid = waitpid(pid, &status, 0)) < 0)

err_sys("waitpid error");

printf("%% ");

}

exit(0);

}