Aros/Developer/Docs/Libraries/ASL

Introduction
Besides the Intuition type requesters, there are the Asl.library requesters that have built in requesters for
 * File Open/Save
 * Font
 * Public Screen selection
 * etc

You need to use AllocAslRequestTags to set up an ASL requester, the reqType can be ASL_FileRequest, ASL_FontRequest or ASL_ScreenModeRequest, you can then optional specify parameters for the ASL requester here or in the AslRequest function such as size of requester, title text, initial file, drawer and file pattern, font information or initial screen information as defined in libraries/asl_intern.h header file.

The AllocAslRequster will return a pointer and can be a pointer to a FileRequester, FontRequester or ScreenModeRequester structure (these are read only). Once a structure is set up, you can call the AslRequest function to display the requester and retrieve data from the structure afterwards such as Filename, Font or ScreenMode for use in your program. Once you have finished with the requester structure, you should call FreeAslRequest.

Values for TagItem in AslRequest function

Font Requester
ASL funcFlags for FontRequester