Line data    Source code

       1              : /*-------------------------------------------------------------------------
       2              :  * link-canary.c
       3              :  *        Detect whether src/common functions came from frontend or backend.
       4              :  *
       5              :  * Copyright (c) 2018-2026, 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
      29          319 : pg_link_canary_is_frontend(void)
      30              : {
      31              : #ifdef FRONTEND
      32          318 :         return true;
      33              : #else
      34            1 :         return false;
      35              : #endif
      36              : }