# &adminguide;

## Overview

gflags module (global flags) keeps a bitmap of flags in shared memory and may be used to change behaviour of server based on value of the flags. Example:

    	if (is_gflag("1")) {
    		t_relay("udp:10.0.0.1:5060");
    	} else {
    		t_relay("udp:10.0.0.2:5060");
    	}

The benefit of this module is the value of the switch flags can be manipulated by external applications such as web interface or command line tools. The size of bitmap is 32.

The module exports external commands that can be used to change the global flags via Management Interface. The MI commands are: set_gflag, reset_gflag and is_gflag.

## Dependencies

The module depends on the following modules (in the other words the listed modules must be loaded before this module):

- none

## Exported Parameters

### `initial` (integer)

The initial value of global flags bitmap.

Default value is 0.

#### `initial` parameter usage

    modparam("gflags", "initial", 15)

## Exported Functions

### `set_gflag(flag)`

Set the bit at the position flag in global flags.

flag can have a value in the range of 0..31.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `set_gflag()` usage

    ...
    set_gflag("4");
    ...

### `reset_gflag(flag)`

Reset the bit at the position flag in global flags.

flag can have a value in the range of 0..31.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `reset_gflag()` usage

    ...
    reset_gflag("4");
    ...

### `is_gflag(flag)`

Check if bit at the position flag in global flags is set.

flag can have a value in the range of 0..31.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE, BRANCH_ROUTE and LOCAL_ROUTE.

#### `is_gflag()` usage

    ...
    if(is_gflag("4"))
    {
    	log("global flag 4 is set\n");
    } else {
    	log("global flag 4 is not set\n");
    };
    ...

## MI Commands

Functions that check or change some flags accepts one parameter which is the flag bitmap/mask specifing the corresponding flags. It is not possible to specify directly the flag position that should be changed as in the functions available in the routing script.

### `set_gflag`

Set the value of some flags (specified by bitmask) to 1.

The parameter value must be a bitmask in decimal or hexa format. The bitmaks has a 32 bit size.

#### `set_gflag` usage

    ...
    $ opensipsctl fifo set_gflag 1
    $ opensipsctl fifo set_gflag 0x3
    ...

### `reset_gflag`

Reset the value of some flags to 0.

The parameter value must be a bitmask in decimal or hexa format. The bitmaks has a 32 bit size.

#### `reset_gflag` usage

    ...
    $ opensipsctl fifo reset_gflag 1
    $ opensipsctl fifo reset_gflag 0x3
    ...

### `is_gflag`

Returns true if the all the flags from the bitmask are set.

The parameter value must be a bitmask in decimal or hexa format. The bitmaks has a 32 bit size.

The function returns TRUE if all the flags from the set are set and FALSE if at least one is not set.

#### `is_gflag` usage

    ...
    $ opensipsctl fifo set_gflag 1024
    $ opensipsctl fifo is_gflag 1024
    TRUE
    $ opensipsctl fifo is_gflag 1025
    TRUE
    $ opensipsctl fifo is_gflag 1023
    FALSE
    $ opensipsctl fifo set_gflag 0x10
    $ opensipsctl fifo is_gflag 1023
    TRUE
    $ opensipsctl fifo is_gflag 1007
    FALSE
    $ opensipsctl fifo is_gflag 16
    TRUE
    ...

### `get_gflags`

Return the bitmap with all flags. The function gets no parameters and returns the bitmap in hexa and decimal format.

#### `get_gflags` usage

    ...
    $ opensipsctl fifo get_gflags
    0x3039
    12345
    ...