setjmp.3: _BSD_SOURCE must be *explicitly* defined to get BSD setjmp() semantics

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man3/setjmp.3 b/man3/setjmp.3
index 6b09c627bc9daaec3d016d21d85f1195756b1e05..98da7afbf8cbd13cf457e6bfb51019b69df3c415 100644 (file)
--- a/man3/setjmp.3
+++ b/man3/setjmp.3
@@ -176,7 +176,9 @@ On Linux with glibc versions before 2.19,
 follows the System V behavior by default,
 but the BSD behavior is provided if the
 .BR _BSD_SOURCE
-feature test macro is defined and none of
+feature test macro is explicitly defined
+.\" so that _FAVOR_BSD is triggered
+and none of
 .BR _POSIX_SOURCE ,
 .BR _POSIX_C_SOURCE ,
 .BR _XOPEN_SOURCE ,