1 /* POSIX compatible write() function.
2 Copyright (C) 2008-2011 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2008.
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program 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
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 /* Replace this function only if module 'nonblocking' or module 'sigpipe' is
25 #if GNULIB_NONBLOCKING || GNULIB_SIGPIPE
27 /* On native Windows platforms, SIGPIPE does not exist. When write() is
28 called on a pipe with no readers, WriteFile() fails with error
29 GetLastError() = ERROR_NO_DATA, and write() in consequence fails with
32 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
38 # define WIN32_LEAN_AND_MEAN /* avoid including junk */
42 rpl_write (int fd, const void *buf, size_t count)
47 ssize_t ret = write (fd, buf, count);
51 # if GNULIB_NONBLOCKING
54 HANDLE h = (HANDLE) _get_osfhandle (fd);
55 if (GetFileType (h) == FILE_TYPE_PIPE)
57 /* h is a pipe or socket. */
59 if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL,
61 && (state & PIPE_NOWAIT) != 0)
63 /* h is a pipe in non-blocking mode.
64 We can get here in four situations:
65 1. When the pipe buffer is full.
66 2. When count <= pipe_buf_size and the number of
67 free bytes in the pipe buffer is < count.
68 3. When count > pipe_buf_size and the number of free
69 bytes in the pipe buffer is > 0, < pipe_buf_size.
70 4. When count > pipe_buf_size and the pipe buffer is
72 The cases 1 and 2 are POSIX compliant. In cases 3 and
73 4 POSIX specifies that write() must split the request
74 and succeed with a partial write. We fix case 4.
75 We don't fix case 3 because it is not essential for
77 DWORD out_size; /* size of the buffer for outgoing data */
78 DWORD in_size; /* size of the buffer for incoming data */
79 if (GetNamedPipeInfo (h, NULL, &out_size, &in_size, NULL))
81 size_t reduced_count = count;
82 /* In theory we need only one of out_size, in_size.
83 But I don't know which of the two. The description
85 if (out_size != 0 && out_size < reduced_count)
86 reduced_count = out_size;
87 if (in_size != 0 && in_size < reduced_count)
88 reduced_count = in_size;
89 if (reduced_count < count)
91 /* Attempt to write only the first part. */
92 count = reduced_count;
96 /* Change errno from ENOSPC to EAGAIN. */
105 if (GetLastError () == ERROR_NO_DATA
106 && GetFileType ((HANDLE) _get_osfhandle (fd))
109 /* Try to raise signal SIGPIPE. */
111 /* If it is currently blocked or ignored, change errno from