1 /*-------------------------------------------------------------------------
2 * link-canary.c
3 * Detect whether src/common functions came from frontend or backend.
4 *
5 * Copyright (c) 2018-2020, PostgreSQL Global Development Group
6 *
7 * IDENTIFICATION
8 * src/common/link-canary.c
9 *
10 *-------------------------------------------------------------------------
11 */
12 #include "c.h"
13
14 #include "common/link-canary.h"
15
16 /*
17 * This function just reports whether this file was compiled for frontend
18 * or backend environment. We need this because in some systems, mainly
19 * ELF-based platforms, it is possible for a shlib (such as libpq) loaded
20 * into the backend to call a backend function named XYZ in preference to
21 * the shlib's own function XYZ. That's bad if the two functions don't
22 * act identically. This exact situation comes up for many functions in
23 * src/common and src/port, where the same function names exist in both
24 * libpq and the backend but they don't act quite identically. To verify
25 * that appropriate measures have been taken to prevent incorrect symbol
26 * resolution, libpq should test that this function returns true.
27 */
28 bool
pg_link_canary_is_frontend(void)29 pg_link_canary_is_frontend(void)
30 {
31 #ifdef FRONTEND
32 return true;
33 #else
34 return false;
35 #endif
36 }
37