I often get asked by customers what the maximum size of the message can be using MAILTOOL.  The answer is not that straightforward since there are a few different ways to set the message.  This will outline those methods and also include their maximum sizes, if there is one for the particular method.

When using the command the max length is 4000 bytes.  But, there are other methods that greatly increase that maximum or eliminate it all together.

1. When using the MAILTOOL command, the maximum size of the message parameter (MESSAGE) is 4096 bytes.
    
2. When using the MAILTOOL command, if you specify *ATT for the message parameter (MESSAGE), this tells MAILTOOL to use the first attachment file listed as the body of the message.  This can be text or html and has no size limit.  This file should exist in the IFS.  Remember if the file contains HTML to set the MIME type to text/html as well.
    
3. If using the MAILTOOL ILE functions, the limit to set the message is 65k. (This is the maximum size of a string in V5R4, which MAILTOOL is compiled to at the time.  This of course will change dramatically when we choose to end support for the old OS versions)
    
4. If using the MAILTOOL ILE functions, there is an option to set the message using a pointer (#mailtool_setMsgPtr()) which is limited in size to the maximum size of a pointer for your OS version.

I hope this helps clear up some things.  As always, feel free to contact us with any questions.