z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

c89, cc, and c++
passing function call parameters in registers. Furthermore, it
reduces the data size by eliminating unused information from
function control blocks.
An XPLINK-compiled program is implicitly a DLL-compiled program
(the C/C++ DLL compiler option need not be specified along with
the XPLINK option). XPLINK improves performance when crossing
function boundaries, even across compilation units, since XPLINK
uses a more efficient linkage mechanism.
For more information about the z/OS C/C++ XPLINK compiler
option, refer to z/OS XL C/C++ User’s Guide. For more information
about Extra Performance Linkage, refer to z/OS Language
Environment Programming Guide.
To use XPLINK, you must both compile and link-edit the program
for XPLINK. All C and C++ source files must be compiled XPLINK,
as you cannot statically link together XPLINK and non-XPLINK C
and C++ object files (with the exception of non-XPLINK ″OS″
linkage). You can however mix XPLINK and non-XPLINK
executables across DLL and fetch() boundaries.
To compile a program as XPLINK, specify the z/OS XL C/C++
XPLINK compiler option. If there are any exported symbols in the
executable and you want to produce a definition side-deck, specify
the DLL link editor option. When XPLINK is specified in the
link-editing step, different link-edit libraries will be used.
Example: Here is an example of compiling and link-editing an
XPLINK application in one command:
c89 -o outxpl -W c,XPLINK -W l,XPLINK,dll file.c
In order to execute an XPLINK program, the SCEERUN2 as well as
the SCEERUN data set must be in the MVS program search order
(see the prefix_PLIB_PREFIX environment variable).
You cannot use -W to override the compiler options that correspond to
c89/cc/c++ options, with the following exceptions:
v Listing options (corresponding to -V)
v Inlining options (corresponding to -O, -2, and -3)
v Symbolic options (corresponding to -s and -g); symbolic options can be
overridden only when neither -s nor -g is specified.
Notes:
1. Most compiler, prelinker, and IPA linker options have a positive and
negative form. The negative form is the positive with a prepended NO
(as in XREF and NOXREF).
2. The compiler #pragma options directives as well as any other #pragma
directives which are overridden by compiler options, will have no effect
in source code compiled by c89/cc/c++.
3. Link editor options must be specified in the name=value format. Both
the option name and value must be spelled out in full. If you do not
specify a value, a default value of YES is used, except for the following
options, which if specified without a value, have the default values
shown here:
ALIASES ALIASES=ALL
80 z/OS V1R9.0 UNIX System Services Command Reference