TLA  Line data    Source code

       1                 : /*-------------------------------------------------------------------------
       2                 :  * link-canary.c
       3                 :  *    Detect whether src/common functions came from frontend or backend.
       4                 :  *
       5                 :  * Copyright (c) 2018-2023, 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 CBC        9538 : pg_link_canary_is_frontend(void)
      30                 : {
      31                 : #ifdef FRONTEND
      32            9233 :     return true;
      33                 : #else
      34             305 :     return false;
      35                 : #endif
      36                 : }