Function CreateDataDirLockFile

src/backend/utils/init/miscinit.c:1391–1395

* Create the data directory lockfile. * * When this is called, we must have already switched the working * directory to DataDir, so we can just use a relative path. This * helps ensure that we are locking the directory we should be. * * Note that the socket directory path line is initially written as empty. * postmaster.c will rewrite it upon creating the first Unix socket. */

 * postmaster.c will rewrite it upon creating the first Unix socket.
 */
void
CreateDataDirLockFile(bool amPostmaster)
{
	CreateLockFile(DIRECTORY_LOCK_FILE, amPostmaster, "", true, DataDir);
}

/*
 * Create a lockfile for the specified Unix socket file.