SQLite

  int nErrMsg = 1+strlen30(sqlite3_errmsg(db));
  char *zErrMsg = sqlite3_malloc64(nErrMsg);
  if( zErrMsg ){
    memcpy(zErrMsg, sqlite3_errmsg(db), nErrMsg);
  }
  return zErrMsg;
}

#ifdef __linux__
/*
** Attempt to display I/O stats on Linux using /proc/PID/io
*/
static void displayLinuxIoStats(FILE *out){
  FILE *in;
  char z[200];
  sqlite3_snprintf(sizeof(z), z, "/proc/%d/io", getpid());
  in = fopen(z, "rb");
  if( in==0 ) return;
  while( fgets(z, sizeof(z), in)!=0 ){
    static const struct {
      const char *zPattern;
      const char *zDesc;
    } aTrans[] = {
      { "rchar: ",                  "Number of bytes received by read():" },
      { "wchar: ",                  "Number of bytes sent to write():"    },
      { "syscr: ",                  "Number of read() system calls:"      },
      { "syscw: ",                  "Number of write() system calls:"     },
      { "read_bytes: ",             "Number of bytes from storage:"       },
      { "write_bytes: ",            "Number of bytes sent to storage:"    },
      { "cancelled_write_bytes: ",  "Cancelled write bytes:"              },
    };
    int i;
    for(i=0; i<ArraySize(aTrans); i++){
      int n = (int)strlen(aTrans[i].zPattern);
      if( strncmp(aTrans[i].zPattern, z, n)==0 ){
        raw_printf(out, "%-36s %s", aTrans[i].zDesc, &z[n]);
        break;
      }
    }
  }
  fclose(in);
}   
#endif


/*
** Display memory stats.
*/
static int display_stats(
  sqlite3 *db,                /* Database to query */
  ShellState *pArg,           /* Pointer to ShellState */

    iCur = sqlite3_stmt_status(pArg->pStmt, SQLITE_STMTSTATUS_SORT, bReset);
    raw_printf(pArg->out, "Sort Operations:                     %d\n", iCur);
    iCur = sqlite3_stmt_status(pArg->pStmt, SQLITE_STMTSTATUS_AUTOINDEX,bReset);
    raw_printf(pArg->out, "Autoindex Inserts:                   %d\n", iCur);
    iCur = sqlite3_stmt_status(pArg->pStmt, SQLITE_STMTSTATUS_VM_STEP, bReset);
    raw_printf(pArg->out, "Virtual Machine Steps:               %d\n", iCur);
  }

#ifdef __linux__
  displayLinuxIoStats(pArg->out);
#endif

  /* Do not remove this machine readable comment: extra-stats-output-here */

  return 0;
}

/*

  ".schema ?TABLE?        Show the CREATE statements\n"
  "                         If TABLE specified, only show tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".separator COL ?ROW?   Change the column separator and optionally the row\n"
  "                         separator for both the output mode and .import\n"
  ".shell CMD ARGS...     Run CMD ARGS... in a system shell\n"
  ".show                  Show the current values for various settings\n"
  ".stats ?on|off?        Show stats or turn stats on or off\n"
  ".system CMD ARGS...    Run CMD ARGS... in a system shell\n"
  ".tables ?TABLE?        List names of tables\n"
  "                         If TABLE specified, only list tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".timeout MS            Try opening locked tables for MS milliseconds\n"
  ".timer on|off          Turn SQL timer on or off\n"
  ".trace FILE|off        Output each SQL statement as it is run\n"

    }
    raw_printf(p->out, "\n");
  }else

  if( c=='s' && strncmp(azArg[0], "stats", n)==0 ){
    if( nArg==2 ){
      p->statsOn = booleanValue(azArg[1]);
    }else if( nArg==1 ){
      display_stats(p->db, p, 0);
    }else{
      raw_printf(stderr, "Usage: .stats ?on|off?\n");
      rc = 1;
    }
  }else

  if( c=='t' && n>1 && strncmp(azArg[0], "tables", n)==0 ){
    sqlite3_stmt *pStmt;
    char **azResult;

} {1 1 1 1 1 1 1 1 1 1}
do_test shell1-3.23.2 {
  # too many arguments
  catchcmd "test.db" ".show BAD"
} {1 {Usage: .show}}

# .stats ON|OFF          Turn stats on or off
#do_test shell1-3.23b.1 {
#  catchcmd "test.db" ".stats"
#} {1 {Usage: .stats on|off}}
do_test shell1-3.23b.2 {
  catchcmd "test.db" ".stats ON"
} {0 {}}
do_test shell1-3.23b.3 {
  catchcmd "test.db" ".stats OFF"
} {0 {}}
do_test shell1-3.23b.4 {
  # too many arguments
  catchcmd "test.db" ".stats OFF BAD"
} {1 {Usage: .stats ?on|off?}}

# .tables ?TABLE?        List names of tables
#                          If TABLE specified, only list tables matching
#                          LIKE pattern TABLE.
do_test shell1-3.24.1 {
  catchcmd "test.db" ".tables"
} {0 {}}

do_test shell4-1.2.2 {
  set res [catchcmd "-stats test.db" ".show"]
  list [regexp {stats: off} $res]
} {0}

# .stats ON|OFF          Turn stats on or off
#do_test shell4-1.3.1 {
#  catchcmd "test.db" ".stats"
#} {1 {Usage: .stats on|off}}
do_test shell4-1.3.2 {
  catchcmd "test.db" ".stats ON"
} {0 {}}
do_test shell4-1.3.3 {
  catchcmd "test.db" ".stats OFF"
} {0 {}}
do_test shell4-1.3.4 {
  # too many arguments
  catchcmd "test.db" ".stats OFF BAD"
} {1 {Usage: .stats ?on|off?}}

# NB. whitespace is important
do_test shell4-1.4.1 {
  set res [catchcmd "test.db" {.show}]
  list [regexp {stats: off} $res]
} {1}