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I believe that there is a way to increase the debug level, but I don't recall how. Perhaps I am using the wrong terms, but web searches and looking on StackExchange are not providing me anything useful. Basically, I want my *Messages* buffer to output more information about an error. How can I do this?

For example, can I set the debug log level to FINE or something similar?

modulitos
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  • You can `trace-function` to print some more info about specific function you have in mind, or you could instrument a function for debugging, in which case Emacs will step-debug the function as it being executed, but anything that goes into `*Messages*` is the result of calling `message` function, and it doesn't have a verbosity setting, however some particular modes to allow you to control the verbosity of their output, like, for example, `flymake-log-level` controls how much info it will print. – wvxvw Aug 30 '15 at 23:13

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If you set variable debug-on-error to t then Emacs will show you a detailed backtrace of what function calls led to the error. (This affects only actual errors, not non-error messages, which are also logged to *Messages*.)

Drew
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  • It's worth noting that there's a dedicated interactive command for doing that: `M-x toggle-debug-on-error`, which will toggle the value of `debug-on-error`. – wvxvw Aug 31 '15 at 13:18
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    @wvxvw: Yes, definitely worth mentioning. But in terms of telling someone how to turn it *on*, it can be confusing. People sometimes have it on without knowing it, and toggling then turns it off. The good news is that since `debug-on-error` is a user *option*, you can as easily do `M-x set-va TAB debug-on-error RET t` as you can do `M-x toggle-debug-on-error RET`. – Drew Aug 31 '15 at 13:24