cpp.1 (2010 09)

c
cpp(1) cpp(1)
-Uname Remove any initial definition of name, where name is a reserved symbol that is
predefined by the particular preprocessor. The current list of these symbols includes:
Operating system:
unix _ _unix
Hardware: hp9000s200 hp9000s300 _ _hp9000s300
hp9000s500 hp9000s800 _ _hp9000s800
hp9000ipc hppa _ _hppa
_PA_RISC1_0 _PA_RISC1_1 _SIO _WSIO
UNIX systems variant: hpux _ _hpux _HPUX_SOURCE
PWB _PWB
lint (1): lint _ _lint
In addition, all symbols that begin with an underscore and either an upper-case letter or
another underscore are reserved. Other symbols may be defined by the
CCOPTS variable
or other command-line options to the C compiler at compile time (see cc(1)). All HP-UX
systems have the symbols
PWB, hpux
, unix, _PWB, __hpux, and __unix defined.
Each system defines at least one hardware variant, as appropriate. The lint symbols are
defined when lint(1) is running. See DEPENDENCIES.
Two special names are understood by
cpp. __LINE__ is defined as the current line number (as a
decimal integer) as counted by
cpp. __FILE__ is defined as the current file name (as a C string) as
known by cpp. They can be used anywhere (including in macros) just as any other defined names.
Directives
All
cpp directives start with lines begun by #. Any number of blanks and tabs are allowed between the
#
and the directive. The directives are:
#define name token-string
Replace subsequent instances of name with token-string . token-string can be null.
#define name(arg, ... , arg) token-string
Replace subsequent instances of name followed by a
(, a list of comma-separated set of
arguments, and a ) by token-string , where each occurrence of an arg in the token-string
is replaced by the corresponding set of tokens in the comma-separated list. When a
macro with arguments is expanded, the arguments are placed into the expanded token-
string unchanged. After the entire token-string has been expanded, cpp restarts its scan
for names to expand at the beginning of the newly created token-string .
Notice that there can be no space between name and the
(.
#endif [text] Ends a section of lines begun by a test directive (
#if
, #ifdef,or#ifndef). Each test
directive must have a matching
#endif. Any text occurring on the same line as the
#endif is ignored and thus may be used to mark matching #if−#endif pairs. This
makes it easier, when reading the source, to match #if, #ifdef, and #ifndef direc-
tives with their associated
#endif directive.
#elif constant-expression
Equivalent to:
#else
#if constant-expression
#else Reverses the notion of the test directive that matches this directive. Thus, if lines previ-
ous to this directive are ignored, the following lines appear in the output, and vice versa.
#if constant-expression
The lines following appear in the output if and only if the constant-expression evaluates
to nonzero. All binary nonassignment C operators, the
?: operator, the unary -, !, and
~ operators are all legal in constant-expression. The precedence of the operators is the
same as defined by the C language.
There is also a unary operator,
defined, which can be used in constant-expression in
these two forms: defined(name) or defined name. This allows the use of #ifdef
and #ifndef in an #if directive.
Only these operators, integer constants, and names that are known by
cpp should be
used in constant-expression. In particular, the sizeof operator is not available.
2 Hewlett-Packard Company − 2 − HP-UX 11i Version 3: September 2010