add documentation

1 files changed, 19 insertions, 0 deletions

diff --git a/src/setjmp/_setjmp.c b/src/setjmp/_setjmp.c
index 922a36dc..a2537915 100644
--- a/src/setjmp/_setjmp.c
+++ b/src/setjmp/_setjmp.c
@@ -1,9 +1,28 @@
 #include <setjmp.h>
 
+/** save program state **/
+
 int _setjmp(jmp_buf env)
 {
 	return setjmp(env);
 }
+
+/***
+saves the current state, without the signal mask, of the calling environment
+in the TYPEDEF(jmp_buf) ARGUMENT(env).
+***/
+
 /*
+CONSTRAINT: entire controlling expression of a selection or iteration statement
+CONSTRAINT: one operand of a relational or equality operator which is the entire controlling expression of a selction or iteration statement
+CONSTRAINT: the operand of a unary ! as the entire controlling expression of a selection or iteration statement
+CONSTRAINT: an entire expression statement
+
+UNSPECIFIED(Whether THIS() is a macro or identifier with external linkage)
+
+UNDEFINED(A macro definition of THIS() is suppressed in order to access an actual function)
+UNDEFINED(A program defines an external identifier named LITERAL(setjmp))
+
 XOPEN(400)
+XOBSOLETE(700, FUNCTION(siglongjmp))
 */