title: Where is FreeBSD libc's _write defined?
body: <p>Where is the code for the <a href="https://github.com/freebsd/freebsd/blob/master/lib/libc/stdio/stdio.c#L65" rel="nofollow">this _write() used in stdio</a>?</p>
  
  <p>A <a href="https://wiki.freebsd.org/AddingSyscalls#Registering_a_syscall" rel="nofollow">wiki page</a> says that every syscall must be registered in a master file and in the a libc's Symbol.map, it also says that for every entry in the Symbol.map three symbols are generated: <code>symbol</code>, <code>_symbol</code>, and <code>sys_symbol</code>.</p>
  
  <p>I found where the sysent for the <a href="https://github.com/freebsd/freebsd/blob/master/sys/kern/syscalls.master#L66-L67" rel="nofollow">write syscall</a>, the <a href="https://github.com/freebsd/freebsd/blob/master/lib/libc/sys/Symbol.map#L1047" rel="nofollow">_write symbol</a> in the <code>Symbol.map</code> but I can't find the actual code for <code>_write</code>.</p>