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

c89, cc, and c++
RECFM
Incorrect values are ignored.
LRECL
None
BLKSIZE
None
DSORG
Incorrect values are treated as if no value had been specified.
22. The following environment variables are parsed as blank-delimited words, and
therefore no embedded blanks or other white-space is allowed in the value
specified. The maximum length of each word is 1024 characters:
prefix_INCDIRS
prefix_INCLIBS
prefix_LIBDIRS
prefix_OPTIONS
prefix_OPERANDS
23. An S-name is a short external symbol name, such as produced by the z/OS
XL C/C++ compiler when compiling z/OS XL C programs with the
NOLONGNAME option. An L-name is a long external symbol name, such as
produced by the z/OS XL C/C++ compiler when compiling z/OS C programs
with the LONGNAME option.
24. The z/OS XL C/C++ run-time library supports a file naming convention of //
(the filename can begin with exactly two slashes). c89/cc/c++ indicate that the
file naming convention of // can be used.
However, the Shell and Utilities feature does not support this convention. Do
not use this convention (//) unless it is specifically indicated (as here in
c89/cc/c++). The z/OS Shell and Utilities feature does support the POSIX file
naming convention where the filename can be selected from the set of
character values excluding the slash and the null character.
25. When coding in C and C++, c89, cc, and c++, by default, produce reentrant
executables. For more information on reentrancy, see z/OS XL C/C++
Programming Guide. When coding in assembler language, the code must not
violate reentrancy. If it does, the resulting executable may not be reentrant.
26. The prefix_CVERSION, prefix_PVERSION and prefix_CLASSVERSION
environment variables are set to a hex string in the format 0xPVVRRMMM
where P is product, VV is version, RR is release and MMM is modification
level. For example, the prefix_CVERSION and prefix_CLASSVERSION for the
z/OS V1R2 compiler is 0x41020000.
27. c89 passes some options to the compiler to ensure that expected behavior is
achieved; for example, POSIX behavior. These options are passed onto the
compiler as defaults that the user can overwrite. When default options passed
by c89 are in conflict with options and/or pragmas that the user specified, the
compiler issues warning and/or severe error messages. Since the user did not
specify options that c89 passed as defaults, these messages may confuse the
user. Prior to the z/OS V1R5 release, the compiler was unable to differentiate
between the options that c89 passed as defaults and the user-specified
options so it was unable to correctly resolve conflicting pragma/option
combinations. In some cases, the compiler would overwrite pragmas with the
options that c89 passed as defaults thus limiting a user’s ability to use
pragmas. As of z/OS V1R5, the compiler is now able to recognize c89 defaults
and avoid confusion from messages for options, which were not explicitly
specified by the user, and overriding pragmas, when the user did not explicitly
request it. It is believed that most users will benefit from this feature so it is the
default behavior. To enable the old behavior, environment variable
Chapter 2. Shell command descriptions 103