diff --git a/src/common/psprintf.c b/src/common/psprintf.c
index 41c39c4..ee2e820 100644
--- a/src/common/psprintf.c
+++ b/src/common/psprintf.c
@@ -97,9 +97,11 @@ size_t
 pvsnprintf(char *buf, size_t len, const char *fmt, va_list args)
 {
 	int			nprinted;
+	int			saved_errno;
 
 	Assert(len > 0);
 
+	saved_errno = errno;
 	errno = 0;
 
 	/*
@@ -129,6 +131,8 @@ pvsnprintf(char *buf, size_t len, const char *fmt, va_list args)
 #endif
 	}
 
+	errno = saved_errno;
+
 	/*
 	 * Note: some versions of vsnprintf return the number of chars actually
 	 * stored, not the total space needed as C99 specifies.  And at least one