# environ_update

- **Language:** C
- **Kind:** function
- **Source:** https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/environ.c#L182
- **Page:** https://libtmux.org/en/tmux/3.2a/reference/c-function-environ_update/

```c
void environ_update(struct options *oo, struct environ *src, struct environ *dst)
```

## Parameters

- `oo` (`struct options *`)
- `src` (`struct environ *`)
- `dst` (`struct environ *`)

## Called by

- [`cmd_attach_session`](/en/tmux/3.2a/reference/c-function-cmd_attach_session/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/cmd-attach-session.c#L125)
- [`cmd_new_session_exec`](/en/tmux/3.2a/reference/c-function-cmd-new-session-c-cmd_new_session_exec/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/cmd-new-session.c#L260)
- [`cmd_switch_client_exec`](/en/tmux/3.2a/reference/c-function-cmd-switch-client-c-cmd_switch_client_exec/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/cmd-switch-client.c#L135)

## Calls

- [`environ_clear`](/en/tmux/3.2a/reference/c-function-environ_clear/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/environ.c#L200)
- [`environ_set`](/en/tmux/3.2a/reference/c-function-environ_set/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/environ.c#L202)
- [`options_array_first`](/en/tmux/3.2a/reference/c-function-options_array_first/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/environ.c#L192)
- [`options_array_item_value`](/en/tmux/3.2a/reference/c-function-options_array_item_value/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/environ.c#L194)
- [`options_array_next`](/en/tmux/3.2a/reference/c-function-options_array_next/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/environ.c#L203)
- [`options_get`](/en/tmux/3.2a/reference/c-function-options_get/) (function) [Call site](https://github.com/tmux/tmux/blob/3b929f332aafa7f1080eacc31feb11ffbb1d1841/environ.c#L189)

## Referenced declarations

- [`environ`](/en/tmux/3.2a/reference/c-struct-environ/) (struct)
- [`environ_entry.name`](/en/tmux/3.2a/reference/c-struct-environ_entry-name/) (attribute)
- [`options`](/en/tmux/3.2a/reference/c-struct-options/) (struct)
- [`options_value.string`](/en/tmux/3.2a/reference/c-union-options_value-string/) (attribute)
- [`environ_entry.value`](/en/tmux/3.2a/reference/c-struct-environ_entry-value/) (attribute)