C/C++ Programmer's Guide (G06.25+)

Using the C Run-Time Library

HP C/C++ Programmer’s Guide for NonStop Systems—429301-008

4-10

Environment-Specific Functions

There are several file-system functions that allow you to operate on a file in the

opposite environment without writing and compiling a separate module for that

environment. These functions are fopen(), freopen(), remove(), rename(),

tmpfile(), and tmpnam(). Each of these functions has environment-specific

variants with suffixes to indicate which type of file you want to operate on. For

example, fopen_guardian() opens a Guardian file in an OSS module and

fopen_oss() opens an OSS file in a Guardian module.

For details, refer to the Open System Services Programmer’s Guide.

Changes Required to Interoperable Compilation Modules at D44

At the D44 release, preexisting TNS/R native C programs that call any of the following

functions to access files in the OSS environment might need to be recompiled with a

native C compiler:

fopen()

fopen_oss()

freopen()

freopen_oss()

remove()

remove_oss()

rename()

rename_oss()

tmpnam()

tmpnam_oss()

tmpfile()

tmpfile_oss()

After the D44 release, each of these functions has a Guardian variant, such as

fopen_guardian(), and each has an OSS variant, such as fopen_oss().

Recompilation is required for compilations made using a compiler released before D44

(G04) if the execution environment is to be D44 or later (G04 or later).

You do not need to recompile Guardian TNS/R native programs that call these

functions to access Guardian files, and OSS programs that call these functions to

access OSS files.

Note. If a TNS module calls any of the environment-specific variants, the feature-test macro

_INTEROPERABLE must be specified when the module is compiled. Specifying

_INTEROPERABLE allows subsequent I/O function calls to know which type of I/O stream they

are operating on.