Age         Owner                  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) 2018-2025, 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
 2605 tgl@sss.pgh.pa.us          29 CBC       13192 : pg_link_canary_is_frontend(void)
                                 30                 : {
                                 31                 : #ifdef FRONTEND
                                 32           13142 :     return true;
                                 33                 : #else
                                 34              50 :     return false;
                                 35                 : #endif
                                 36                 : }