| 摘要 |
<p>When a first application program (33) raises an error condition, a context switch (33,34,35), in one embodiment, transfers control to one of several Help programs (36), as selected automatically without user or system operator intervention. Such a first application program (33) operates on a computer system (10) that includes a file system (50), a data structure (35) in memory (30), and a processor (20) that executes in sequence an operating system (32), the first application program (33), a constructor (34), and a second application program (36), for example, a Help program. For each candidate Help program (36,56), the constructor (34) looks for prerequisite files (52,54,58) in the file system (50). If a candidate Help program's prerequisites are met, the constructor (34) sets a link value in the data structure (35) that directs a subsequent call from the first application program (33) to the Help program (36) selected by the constructor (34). In a second embodiment, a general method of developing the first application program (33) for context switching incorporates the step of including (210), in the first application program (33), a transfer of control (220) to a destination program (36) identified by a constructor (34), wherein the constructor (34), precluding manual direction by an operator, identifies the destination program (36) from several candidates (36,56) by testing an operational prerequisite (58). <IMAGE></p> |
