As I know there isn't way to add some .inc file only if file exist (i.e. don't generate error when file is absent but include nothing). May be worth add this feature (or give simple source patch for it)?

I second the request!

Out of curiosity: I tried to imagine a scenario where such capacity might be useful, but didn't find one. In all scenarios that came to mind, including a file that does not exist was a programmer error, on which the assembler should in fact abort. Could someone enlighten me? Thank you.

for each use of such thing i can imagine exists also another nice solution wby existing and more common ways

In my Reva Forth program, it is possible for a person to create a 'custom' version with his own code inside. I need to include (actually, I use 'file') custom code only if it exists.

What I currently do, is concatenate the sources outside of FASM and then use 'file' on the resultant combination. Similarly if one wanted to conditionally include a file.

Thank you ronware, I see that I was lacking phantasy. An obvious follow-up question is: "Wouldn't it be better to always require the presence of the custom-user-code file, just to make sure that everything is in its proper place? -- If they don't have any custom code, the file may be zero bytes long." But that's clearly a matter of personal preference, so I won't ask the question.