C語言的readlink

C語言的readlink

read value of a symbolic link。

ssize_t readlink(const char *path, char *buf, size_t bufsiz);

readlink() places the contents of the symbolic link path in the buffer buf, which has size bufsiz. readlink() does not append a null byte to buf. 把path所指的符號串連中對應的檔案路徑放到buf中，最多bufsiz個位元組。

樣本

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include "sys/types.h"

#include <sys/stat.h>

#include <fcntl.h>

//#include <>

int get_pathname_from_fd(int fd, char pathname[], int n)

{

char buf[1024];

pid_t pid;

bzero(buf, 1024);

pid = getpid();

snprintf(buf, 1024, "/proc/%i/fd/%i", pid, fd);

return readlink(buf, pathname, n);

}

int main(void)

{

int fd;

char pathname[4096];

bzero(pathname, 4096);

fd = open("/tmp/foo", O_CREAT|O_RDONLY);

get_pathname_from_fd(fd, pathname, 4096);

printf("fd=%d; pathname=%s\n", fd, pathname);

return 0;

}