[from mainstream slang meaning 'vomit']
1. interj. Term of disgust. This is the closest hackish equivalent of the Val\-speak "gag me with a spoon". (like ewww!)
2. vi. To say "Barf!" or emit some similar expression of disgust. "I showed him my latest hack and he barfed" means only that he complained about it, not that he literally vomited.
3. vi. To fail to work because of unacceptable input. May mean to give an error message.
Examples: "The division operation barfs if you try to divide by 0." (That is, the division operation checks for an attempt to divide by zero, and if one is encountered it causes the operation to fail in some unspecified, but generally obvious, manner.) "The text editor barfs if you try to read in a new file before writing out the old one."