1#ifndef __sigval_t_defined
2#define __sigval_t_defined
3
4#include <bits/types/__sigval_t.h>
5
6/* To avoid sigval_t (not a standard type name) having C++ name
7 mangling depending on whether the selected standard includes union
8 sigval, it should not be defined at all when using a standard for
9 which the sigval name is not reserved; in that case, headers should
10 not include <bits/types/sigval_t.h> and should use only the
11 internal __sigval_t name. */
12#ifndef __USE_POSIX199309
13# error "sigval_t defined for standard not including union sigval"
14#endif
15
16typedef __sigval_t sigval_t;
17
18#endif
19

source code of glibc/signal/bits/types/sigval_t.h