fgetc()

(PHP 4, PHP 5, PHP 7)

从文件指针中读取字符

说明

fgetc(resource $handle): string

从文件句柄中获取一个字符。

参数

$handle: 文件指针必须是有效的，必须指向由fopen()或fsockopen()成功打开的文件(并还未由fclose()关闭)。

返回值

返回一个包含有一个字符的字符串，该字符从$handle指向的文件中得到。碰到 EOF 则返回FALSE。

Warning
此函数可能返回布尔值FALSE，但也可能返回等同于FALSE的非布尔值。请阅读布尔类型章节以获取更多信息。应使用===运算符来测试此函数的返回值。

范例

一个fgetc()例子

<?php
$fp = fopen('somefile.txt', 'r');
if (!$fp) {
    echo 'Could not open file somefile.txt';
}
while (false !== ($char = fgetc($fp))) {
    echo "$char\n";
}
?>

注释

Note:此函数可安全用于二进制对象。

参见

fread() 读取文件（可安全用于二进制文件）
fopen() 打开文件或者 URL
popen() 打开进程文件指针
fsockopen() 打开一个网络连接或者一个Unix套接字连接
fgets() 从文件指针中读取一行

The best and simplest way to get input from a user in the CLI with only PHP is to use fgetc() function with the STDIN constant:
<?php
echo 'Are you sure you want to quit? (y/n) ';
$input = fgetc(STDIN);
if ($input == 'y')
{
  exit(0);
}
?>

I was using command-line PHP to create an interactive script and wanted the user to enter just one character of input - in response a Yes/No question. Had some trouble finding a way to do so using fgets(), fgetc(), various suggestions using readline(), popen(), etc. Came up with the following that works quite nicely:
$ans = strtolower( trim( `bash -c "read -n 1 -t 10 ANS ; echo \\\$ANS"` ) );

To read a single key-press in CLI mode, you can either use ncurses (which will probably require additional modules for PHP) or get nasty with the *nix "/bin/stty" command)
<?php
  function stty($options) {
   exec($cmd = "/bin/stty $options", $output, $el);
   $el AND die("exec($cmd) failed");
   return implode(" ", $output);
  }
  function getchar($echo = false) {
   $echo = $echo ? "" : "-echo";
   # Get original settings
   $stty_settings = preg_replace("#.*; ?#s", "", stty("--all"));
   # Set new ones
   stty("cbreak $echo");
   # Get characters until a PERIOD is typed, 
   # showing their hexidecimal ordinal values.
   printf("> ");
   do {
     printf("%02x ", ord($c = fgetc(STDIN)));
   } while ($c != '.');
   # Return settings
   stty($stty_settings);
  }
  getchar();
?>

You can't just simple print separated characters of a text which is encoded in multibyte character set like this;
Because fgetc() will break each multibyte character on its every byte. Consider this example: 
<?php
$path = 'foo/cyrillic.txt';
$handle = fopen($path, 'rb');
while (FALSE !== ($ch = fgetc($handle))) {
  $curs = ftell($hanlde);
  print "[$curs:] $ch\n";
}
/* The result will be something like this:
<
[1]: <
[2]: h
[3]: 2
[4]: >
[5]: 
[6]: 
[7]: 
[8]: 
[9]: 
[10]: 
[11]: 
[12]: 
[13]: 
[14]: 
[15]: 
[16]: 
*/ ?>
I don't think this is the best, but it can be a workaround:
<?php
$path = 'path/to/your/file.ext';
if (!$handle = fopen($path, 'rb')) {
  echo "Can't open ($path) file';
  exit;
}
$mbch = '';  // keeps the first byte of 2-byte cyrillic letters
while (FALSE !== ($ch = fgetc($handle))) {    
  //check for the sign of 2-byte cyrillic letters  
  if (empty($mbch) && (FALSE !== array_search(ord($ch), Array(208,209,129)))) {
    $mbch = $ch;  // keep the first byte
    continue;
  }
  $curs = ftell($handle);
  print "[$curs]: " . $mbch . $ch . PHP_EOL;
  // or print "[$curs]: $mbch$ch\n";
  if (!empty($mbch)) $mbch = '';  // erase the byte after using
}
?>

If you call fgetc(HANDLE) multiple times you must clear buffer before, thus get all unwanted chars to the new new line character.
while (true) {
  //clear buffer - read all unwanted characters
  while(fgetc(STDIN) != "\n");
  
  //get first character from STDIN
  $first = fgetc(STDIN);
}