Introduction to Pathmaker

Types of Pathmaker Applications
Pathmaker Applications
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The Pathmaker product supplies a common service utility library that contains
functions, constants, and definitions that can be referenced by code in a custom source
file. The common service library includes constants for common Enscribe and
NonStop SQL file system error codes, and functions for formatting error messages,
manipulating certain character strings, and so on.
A generated source file is created by the Pathmaker product when a C custom service
is generated. A generated source file contains C code that the Pathmaker product
creates for such items as the service’s request and reply message data structure
definitions, data structure definitions for each logical file accessed by the service, and
host variables for NonStop SQL tables. The generated source file for a service
references the service’s custom source file.
The Pathmaker product uses the generated source file as the primary input file when
compiling a C service. C services can be generated and compiled separately outside of
any server or they can be generated and compiled as part of a server generation and
compile operation. In either case, a separate nonrunnable object file is created for each
C service compiled.
Application developers package custom C services into custom C servers and then
initiate the generation and compilation of those servers. When a C server is compiled,
the object files for the included C services are bound into the server.
When a C server generated by the Pathmaker product is run, it receives a message
from a requester, invokes the appropriate function (that is, service) to process the
request, and returns a reply to the requester. To make this series of actions work, the
Pathmaker product provides the following in each custom C server it generates:
Overall program control logic
Code to handle messages in the $RECEIVE file
Error logic
Logical file opens, including the passing of file descriptors to the services using
control parameters
Logical file closes
Support for MAKE Utilities. The Pathmaker product provides limited support for
compiling C services and servers using an external MAKE utility. (A MAKE utility is
a tool commonly found in C program development environments that is used to
compile only those objects that are not current with respect to other objects that they
depend upon.) Although the Pathmaker product does not supply a MAKE utility, it
does support the use of such a utility by updating the timestamp of a generated source
file when the definition of the service or server in the project catalog has been changed,
and by allowing application developers to generate a service or server without
immediate compilation.