[4.0] cb07d86 Squash warnings for warn_unused_result.

[Lasse Karstensen]

commit cb07d86cbb0b99f941aeead613d564a40b8e1c50
Author: Lasse Karstensen <lkarsten at varnish-software.com>
Date:   Thu Sep 4 12:56:47 2014 +0200

    Squash warnings for warn_unused_result.

diff --git a/lib/libvarnish/vlu.c b/lib/libvarnish/vlu.c
index 610ca8b..5498f11 100644
--- a/lib/libvarnish/vlu.c
+++ b/lib/libvarnish/vlu.c
@@ -96,6 +96,7 @@ vlu_dotelnet(struct vlu *l, char *p)
 	char *e;
 	char tno[3];
 	int i;
+	ssize_t r = 0;
 
 	e = l->buf + l->bufp;
 	assert(p >= l->buf && p < e);
@@ -120,7 +121,9 @@ vlu_dotelnet(struct vlu *l, char *p)
 		/* Return WONT for these */
 		memcpy(tno, p, 3);
 		tno[1] = (char)252;
-		(void)write(l->telnet, tno, 3);
+		r = write(l->telnet, tno, 3);
+		if (r != 3)
+			return (1);
 		i = 3;
 		break;
 	default:
diff --git a/lib/libvarnishapi/vsl.c b/lib/libvarnishapi/vsl.c
index 6e0f20a..7319253 100644
--- a/lib/libvarnishapi/vsl.c
+++ b/lib/libvarnishapi/vsl.c
@@ -408,6 +408,7 @@ VSL_WriteOpen(struct VSL_data *vsl, const char *name, int append, int unbuf)
 {
 	const char head[] = VSL_FILE_ID;
 	FILE* f;
+	size_t r = 0;
 
 	f = fopen(name, append ? "a" : "w");
 	if (f == NULL) {
@@ -417,7 +418,12 @@ VSL_WriteOpen(struct VSL_data *vsl, const char *name, int append, int unbuf)
 	if (unbuf)
 		setbuf(f, NULL);
 	if (0 == ftell(f))
-		fwrite(head, 1, sizeof head, f);
+		r = fwrite(head, 1, sizeof head, f);
+		if (r != sizeof head) {
+			vsl_diag(vsl, "%s", strerror(errno));
+			fclose(f);
+			return (NULL);
+		}
 	return (f);
 }