如何使用write（）系统调用将整数写入文件中

Question

如何使用write（）系统调用将整数写入文件中

 //write(fd,buffer,strlen(buffer));
 //The buffer in the write() system call has to be an char[]; 
 //if i want to write integer such as 

for(int i = 0, i < 10; i++){

    write(fd,i.??); // error 
    // How can i write the integer in to the file by using the write() system call
}

Answer 1

如果要二进制输出：

 write(fd, &i, sizeof(i));

如果要输出文本，每行十进制数字：

char tmpbuf[50];
int n = sprintf(tmpbuf, "%d\n", i);
write(fd, tmpbuf, n);

如果要输出文本，则每个int 8个十六进制数字：

char tmpbuf[20];
int n = sprintf(tmpbuf, "%08X", i);
write(fd, tmpbuf, n);

Answer 2

您可以先使用sprintf()函数创建字符串，然后在write()中使用它，例如：

char number_s[2];
sprintf(number_s,"%2d",i);
write(fd,number_s,strlen(number_s));