From: Martin Ling <redacted>
Date: Sat, 25 Jan 2020 14:51:56 +0000 (+0000)
Subject: Fix building on Cygwin.
X-Git-Url: https://sigrok.org/gitweb/?p=libserialport.git;a=commitdiff_plain;h=2be41b1265e9c433a1a2af435e040388453fc603

Fix building on Cygwin.

There were two issues: first, feature test macros were only defined
for __linux__, so defintions we needed were not included. Enable the
same feature test macros for __CYGWIN__.

Second, the Cygwin headers do not define TIOCOUTQ, needed to use
ioctl() to get the number of bytes in the output queue. Return
SP_ERR_SUPP on Cygwin for this operation.

This fixes bug #963.
---

diff --git a/libserialport_internal.h b/libserialport_internal.h
index 20b3505..5b811cc 100644
--- a/libserialport_internal.h
+++ b/libserialport_internal.h
@@ -27,8 +27,8 @@
 #define _CRT_SECURE_NO_WARNINGS
 #endif
 
-/* These Linux/glibc specific defines must appear before other headers.*/
-#ifdef __linux__
+/* These feature test macros must appear before other headers.*/
+#if defined(__linux__) || defined(__CYGWIN__)
 /* For timeradd, timersub, timercmp, realpath. */
 #define _BSD_SOURCE 1 /* for glibc < 2.19 */
 #define _DEFAULT_SOURCE 1 /* for glibc >= 2.20 */
diff --git a/serialport.c b/serialport.c
index 422b767..eda2d19 100644
--- a/serialport.c
+++ b/serialport.c
@@ -1307,6 +1307,11 @@ SP_API enum sp_return sp_output_waiting(struct sp_port *port)
 {
 	TRACE("%p", port);
 
+#ifdef __CYGWIN__
+	/* TIOCOUTQ is not defined in Cygwin headers */
+	RETURN_ERROR(SP_ERR_SUPP,
+			"Getting output bytes waiting is not supported on Cygwin");
+#else
 	CHECK_OPEN_PORT();
 
 	DEBUG_FMT("Checking output bytes waiting on port %s", port->name);
@@ -1324,6 +1329,7 @@ SP_API enum sp_return sp_output_waiting(struct sp_port *port)
 		RETURN_FAIL("TIOCOUTQ ioctl failed");
 	RETURN_INT(bytes_waiting);
 #endif
+#endif
 }
 
 SP_API enum sp_return sp_new_event_set(struct sp_event_set **result_ptr)