From: Bart Van Assche <bvanassche@acm.org>
Date: Sat, 4 Jul 2020 03:20:00 +0000 (-0700)
Subject: os/windows/posix.c: Use INVALID_SOCKET instead of < 0
X-Git-Tag: fio-3.21~13^2
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=2ec7cd03ea848cf1ae9e7a4be1160b57ec12bd61;p=fio.git

os/windows/posix.c: Use INVALID_SOCKET instead of < 0

From
https://docs.microsoft.com/en-us/windows/win32/winsock/socket-data-type-2:
"Because the SOCKET type is unsigned, compiling existing source code from,
for example, a UNIX environment may lead to compiler warnings about
signed/unsigned data type mismatches.

This means, for example, that checking for errors when the socket and
accept functions return should not be done by comparing the return value
with -1, or seeing if the value is negative (both common and legal
approaches in UNIX). Instead, an application should use the manifest
constant INVALID_SOCKET as defined in the Winsock2.h header file."

This patch fixes the following build error for the latest version of
the MinGW64 cross-compiler on Cygwin:

os/windows/posix.c:886:17: error: comparison of unsigned expression < 0
  is always false

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---

diff --git a/os/windows/posix.c b/os/windows/posix.c
index 729d1b1f..31271de0 100644
--- a/os/windows/posix.c
+++ b/os/windows/posix.c
@@ -883,7 +883,7 @@ int poll(struct pollfd fds[], nfds_t nfds, int timeout)
 	FD_ZERO(&exceptfds);
 
 	for (i = 0; i < nfds; i++) {
-		if (fds[i].fd < 0) {
+		if (fds[i].fd == INVALID_SOCKET) {
 			fds[i].revents = 0;
 			continue;
 		}
@@ -900,7 +900,7 @@ int poll(struct pollfd fds[], nfds_t nfds, int timeout)
 
 	if (rc != SOCKET_ERROR) {
 		for (i = 0; i < nfds; i++) {
-			if (fds[i].fd < 0)
+			if (fds[i].fd == INVALID_SOCKET)
 				continue;
 
 			if ((fds[i].events & POLLIN) && FD_ISSET(fds[i].fd, &readfds))