Where Online Learning is simpler!

The C and C++ Include Header Files

cat -n /usr/include/x86_64-linux-gnu/bits/socket2.h

     1	/* Checking macros for socket functions.
     2	   Copyright (C) 2005-2026 Free Software Foundation, Inc.
     3	   This file is part of the GNU C Library.
     4	
     5	   The GNU C Library is free software; you can redistribute it and/or
     6	   modify it under the terms of the GNU Lesser General Public
     7	   License as published by the Free Software Foundation; either
     8	   version 2.1 of the License, or (at your option) any later version.
     9	
    10	   The GNU C Library is distributed in the hope that it will be useful,
    11	   but WITHOUT ANY WARRANTY; without even the implied warranty of
    12	   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13	   Lesser General Public License for more details.
    14	
    15	   You should have received a copy of the GNU Lesser General Public
    16	   License along with the GNU C Library; if not, see
    17	   <https://www.gnu.org/licenses/>.  */
    18	
    19	#ifndef _SYS_SOCKET_H
    20	# error "Never include <bits/socket2.h> directly; use <sys/socket.h> instead."
    21	#endif
    22	
    23	extern ssize_t __recv_chk (int __fd, void *__buf, size_t __n, size_t __buflen,
    24				   int __flags);
    25	extern ssize_t __REDIRECT (__recv_alias, (int __fd, void *__buf, size_t __n,
    26						  int __flags), recv);
    27	extern ssize_t __REDIRECT (__recv_chk_warn,
    28				   (int __fd, void *__buf, size_t __n, size_t __buflen,
    29				    int __flags), __recv_chk)
    30	     __warnattr ("recv called with bigger length than size of destination "
    31			 "buffer");
    32	
    33	__fortify_function __attribute_overloadable__ ssize_t
    34	recv (int __fd, __fortify_clang_overload_arg0 (void *, ,__buf), size_t __n,
    35	      int __flags)
    36	     __fortify_clang_warning_only_if_bos0_lt (__n, __buf,
    37						      "recv called with bigger length than "
    38						      "size of destination buffer")
    39	{
    40	  size_t __sz = __glibc_objsize0 (__buf);
    41	  if (__glibc_safe_or_unknown_len (__n, sizeof (char), __sz))
    42	    return __recv_alias (__fd, __buf, __n, __flags);
    43	#if !__fortify_use_clang
    44	  if (__glibc_unsafe_len (__n, sizeof (char), __sz))
    45	    return __recv_chk_warn (__fd, __buf, __n, __sz, __flags);
    46	#endif
    47	  return __recv_chk (__fd, __buf, __n, __sz, __flags);
    48	}
    49	
    50	extern ssize_t __recvfrom_chk (int __fd, void *__restrict __buf, size_t __n,
    51				       size_t __buflen, int __flags,
    52				       __SOCKADDR_ARG __addr,
    53				       socklen_t *__restrict __addr_len);
    54	extern ssize_t __REDIRECT (__recvfrom_alias,
    55				   (int __fd, void *__restrict __buf, size_t __n,
    56				    int __flags, __SOCKADDR_ARG __addr,
    57				    socklen_t *__restrict __addr_len), recvfrom);
    58	extern ssize_t __REDIRECT (__recvfrom_chk_warn,
    59				   (int __fd, void *__restrict __buf, size_t __n,
    60				    size_t __buflen, int __flags,
    61				    __SOCKADDR_ARG __addr,
    62				    socklen_t *__restrict __addr_len), __recvfrom_chk)
    63	     __warnattr ("recvfrom called with bigger length than size of "
    64			 "destination buffer");
    65	
    66	__fortify_function __attribute_overloadable__ ssize_t
    67	recvfrom (int __fd, __fortify_clang_overload_arg0 (void *, __restrict, __buf),
    68		  size_t __n, int __flags,
    69		  __SOCKADDR_ARG __addr, socklen_t *__restrict __addr_len)
    70	     __fortify_clang_warning_only_if_bos0_lt (__n, __buf,
    71						      "recvfrom called with bigger length "
    72						      "than size of destination buffer")
    73	{
    74	  size_t __sz = __glibc_objsize0 (__buf);
    75	  if (__glibc_safe_or_unknown_len (__n, sizeof (char), __sz))
    76	    return __recvfrom_alias (__fd, __buf, __n, __flags, __addr, __addr_len);
    77	#if !__fortify_use_clang
    78	  if (__glibc_unsafe_len (__n, sizeof (char), __sz))
    79	    return __recvfrom_chk_warn (__fd, __buf, __n, __sz, __flags, __addr,
    80					__addr_len);
    81	#endif
    82	  return __recvfrom_chk (__fd, __buf, __n, __sz, __flags, __addr, __addr_len);
    83	}