SendClientMessage

From SA-MP Wiki

Description:

This function sends a message to a specific player with a chosen color in the chat. The whole line in the chatbox will be in the set color unless color embedding is used (0.3c or later).

Parameters:

(playerid, color, const message[])

playerid

The ID of the player to display the message to.

color

The color of the message (0xRRGGBBAA Hex format).

const message[]

The text that will be displayed (max 144 characters).

Return Values:

1: The function executed successfully. Success is reported when the string is over 144 characters, but the message won't be sent.
0: The function failed to execute. The player is not connected.

Important
Notes

If a message is longer than 144 characters, it will not be sent. Truncation can be used to prevent this. Displaying a message on multiple lines will also solve this issue.
Avoid using the percent sign (or format specifiers) in the actual message text without properly escaping it (like %%). It will result in crashes otherwise.

Example Usage:

#define COLOR_RED 0xFF0000FF
 
public OnPlayerConnect(playerid)
{
    SendClientMessage(playerid, COLOR_RED, "This text is red");
    SendClientMessage(playerid, 0x00FF00FF, "This text is green.");
    SendClientMessage(playerid, -1, "This text is white.");
    return 1;
}

Tips

You can use color embedding for multiple colors in the message.
Using '-1' as the color will make the text white (for the simple reason that -1, when represented in hexadecimal notation, is 0xFFFFFFFF).

[edit]