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action is not described

activate_(plugin) action-hook . WP 2.0.0

Fires as a specific plugin is being activated.

This hook is the "activation" hook used internally by register_activation_hook(). The dynamic portion of the hook name, $plugin, refers to the plugin basename.

If a plugin is silently activated (such as during an update), this hook does not fire.

Usage

add_action( 'activate_(plugin)', 'action_function_name_8878' );
function action_function_name_8878( $network_wide ){
	// action...
}
$network_wide(true/false)
Whether to enable the plugin for all sites in the network or just the current site. Multisite only.
Default: false

Where the hook is called

activate_plugin()
wp-admin/includes/plugin.php 598
do_action( "activate_{$plugin}", $network_wide );
wp-admin/plugins.php 174
do_action( "activate_{$plugin}" );

Where the hook is used (in WP core)

wp-includes/default-filters.php 521
add_action( 'activate_header', '_wp_admin_bar_init' );