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Overview
Comment:Fix a benign data race in os_unix.c that might trouble tsan and similar tools.
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SHA3-256: 95806ac1dabe4598170061d903ae30f09bafac149ff6696963a7e056ac846cdb
User & Date: dan 2021-11-19 14:02:43
Context
2021-11-19
19:11
Small performance increase and size reduction for sqlite3ExprCompare(). This change also handles some corner cases without the need for ALWAYS(). (check-in: d814ba6e user: drh tags: trunk)
14:02
Fix a benign data race in os_unix.c that might trouble tsan and similar tools. (check-in: 95806ac1 user: dan tags: trunk)
2021-11-18
20:56
Minor tweaks to the way auxiliary tools are built, to make it easier to customize the builds without having to alter the code. (check-in: 90b06b6f user: drh tags: trunk)
Changes
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Changes to src/os_unix.c.

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  }else{
    pId->pMethods = pLockingStyle;
    OpenCounter(+1);
    verifyDbFile(pNew);
  }
  return rc;
}





















/*
** Return the name of a directory in which to put temporary files.
** If no suitable temporary file directory can be found, return NULL.
*/
static const char *unixTempFileDir(void){
  static const char *azDirs[] = {
     0,
     0,
     "/var/tmp",
     "/usr/tmp",
     "/tmp",
     "."
  };
  unsigned int i = 0;
  struct stat buf;
  const char *zDir = sqlite3_temp_directory;

  if( !azDirs[0] ) azDirs[0] = getenv("SQLITE_TMPDIR");
  if( !azDirs[1] ) azDirs[1] = getenv("TMPDIR");
  while(1){
    if( zDir!=0
     && osStat(zDir, &buf)==0
     && S_ISDIR(buf.st_mode)
     && osAccess(zDir, 03)==0
    ){
      return zDir;
    }
    if( i>=sizeof(azDirs)/sizeof(azDirs[0]) ) break;
    zDir = azDirs[i++];
  }
  return 0;
}

/*
** Create a temporary file name in zBuf.  zBuf must be allocated
** by the calling process and must be big enough to hold at least







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  }else{
    pId->pMethods = pLockingStyle;
    OpenCounter(+1);
    verifyDbFile(pNew);
  }
  return rc;
}

/*
** Directories to consider for temp files.
*/
static const char *azTempDirs[] = {
  0,
  0,
  "/var/tmp",
  "/usr/tmp",
  "/tmp",
  "."
};

/*
** Initialize first two members of azTempDirs[] array.
*/
static void unixTempFileInit(void){
  azTempDirs[0] = getenv("SQLITE_TMPDIR");
  azTempDirs[1] = getenv("TMPDIR");
}

/*
** Return the name of a directory in which to put temporary files.
** If no suitable temporary file directory can be found, return NULL.
*/
static const char *unixTempFileDir(void){








  unsigned int i = 0;
  struct stat buf;
  const char *zDir = sqlite3_temp_directory;



  while(1){
    if( zDir!=0
     && osStat(zDir, &buf)==0
     && S_ISDIR(buf.st_mode)
     && osAccess(zDir, 03)==0
    ){
      return zDir;
    }
    if( i>=sizeof(azTempDirs)/sizeof(azTempDirs[0]) ) break;
    zDir = azTempDirs[i++];
  }
  return 0;
}

/*
** Create a temporary file name in zBuf.  zBuf must be allocated
** by the calling process and must be big enough to hold at least
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  **    READ-2      UNIX_SHM_BASE+5    125
  **    READ-3      UNIX_SHM_BASE+6    126
  **    READ-4      UNIX_SHM_BASE+7    127
  **    DMS         UNIX_SHM_BASE+8    128
  */
  assert( UNIX_SHM_DMS==128   );  /* Byte offset of the deadman-switch */
#endif




  return SQLITE_OK; 
}

/*
** Shutdown the operating system interface.
**







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  **    READ-2      UNIX_SHM_BASE+5    125
  **    READ-3      UNIX_SHM_BASE+6    126
  **    READ-4      UNIX_SHM_BASE+7    127
  **    DMS         UNIX_SHM_BASE+8    128
  */
  assert( UNIX_SHM_DMS==128   );  /* Byte offset of the deadman-switch */
#endif

  /* Initialize temp file dir array. */
  unixTempFileInit();

  return SQLITE_OK; 
}

/*
** Shutdown the operating system interface.
**