-.TH CPP VI
+.TH CPP 6ACK
.SH NAME
cpp \- C Pre-Processor
.SH SYNOPSIS
-cpp [\-options] files
+cpp [\-options] [ file ]
.SH DESCRIPTION
.I Cpp
-reads one or more files, expands macros and include
+reads a file, expands macros and include
files, and writes an input file for the C compiler.
-All output is to cpp.tmp (cpp.tmp.c on Unix).
+All output is to standard output.
.br
-The following options are supported. On non-Unix systems,
-options may be given in either case.
-.IP -Ofile
-Output to this file, instead of the default.
-.IP -S
-Output to stdout, instead of the default.
-.IP -Idirectory
-Add this directory to the list of
+The following options are supported.
+.IP -\fBI\fIdirectory\fR
+.br
+add this directory to the list of
directories searched for #include "..." and #include <...>
commands. Note that there is no space between the
"-I" and the directory string. More than one -I command
is permitted.
-.IP -L
-.I Cpp
-transmits line number information to
-the C compiler by outputting "#line <number>" records.
-If the -L option is given, this record will be transmitted
-as "#", allowing the output of
-.I cpp
-to be input to a compiler
-without an intervening preprocessor without error.
-.IP -Dname=value
-Define the name as if the programmer wrote
-.br
-.nf
- #define name value
-.fi
-.br
-at the start of the first file. If "=value" is not
-given, a value of "1" will be used.
-.br
-On non-unix systems, all alphabetic text will be forced
-to upper-case.
-.br
-.IP -Uname
-Undefine the name as if
-.br
-.nf
- #undef name
-.fi
-.br
-were given. On non-Unix systems, "name" will be forced to
-upper-case.
+.IP -\fBI\fR
+end the list of directories to be searched, and also do not look in
+default places.
+.IP -\fBD\fIname\fR=\fItext\fR
+.br
+define
+.I name
+as a macro with
+.I text
+as its replacement text.
+.IP -\fBD\fIname\fR
+the same as -\fBD\fIname\fR=1.
+.IP
+.IP -\fBU\fIname\fR
+.br
+undefine the macro name
+.IR name .
+.IP -\fBC\fR
+leave comments in. By default, C-comments are deleted.
+.IP -\fBP\fR
+do not generate line directives
+.IP -\fBM\fIn\fR
+set maximum identifier length to
+.IR n .
+.PP
The following names are always available unless undefined:
.RS
.IP __FILE__
The date and time of compilation as
a Unix ctime quoted string (the trailing newline is removed).
.RE
-Thus,
-.br
-.nf
- printf("Bug at line %s,", __LINE__);
- printf(" source file %s", __FILE__);
- printf(" compiled on %s", __DATE__);
-.fi
-.IP
--Xnumber
-Enable debugging code. If no value is
-given, a value of 1 will be used. (For maintenence of
-.I cpp
-only.)
-.SH "COMMENTS IN MACRO TEXT AND ARGUMENT CONCATENATION"
-.br
-Comments are removed from the input text. The comment
-characters serve as an invisible token delimiter. Thus,
-the macro
-.nf
- #define CAT(a, b) b/**/a
- int value = CAT(1, 2);
-.fi
-Will generate "int value = 21;".
-.br
-A better way of concatenating arguments is as follows:
-.nf
- #define I(x)x
- #define CAT(x,y)I(x)y
- int value = CAT(1, 2);
-.fi
-If the above macros are defined without extraneous
-spaces, they will be transportable to other implementations.
-.br
-.SH DIFFERENCES
-.br
-The following is a list of differences between this
-pre-processor and the Unix V7 preprocessor which was
-written by John Reiser. It is probably not complete.
-.IP o
-Macro formal parameters are recognized within
-quoted strings and character constants in macro definitions.
-For example,
-.nf
- #define foo(a) "Today is a"
- printf(foo(tuesday));
-.fi
-Would print "Today is tuesday".
-.br
-Recognition of formal parameters in macro replacement
-strings is not permitted by the Draft ANSI C Standard.
-It is permitted in this implementation if cpp was
-compiled with the STRING_FORMAL parameter set appropriately.
-.br
-Unlike Reiser's implementation, the '\e' "quote next character"
-does just that. I.e.
-.nf
- #define foo(a) "Today is \ea a"
- printf(foo(tuesday));
-.fi
-Would print "Today is a tuesday". Note that this may
-not be portable.
-.IP o
-Reiser's implementation removes "escaped" linefeeds
-(The two character sequence \e<LF>) within macros. This
-implementation preserves them. For example, a macro which
-generates control commands might be written
-.nf
- #define foo(a, b) \e
- #define a b \e
-.fi
-.nf
- foo(fubar, foobar)
- int fubar;
-.fi
-The above would generate "int foobar;" and a warning message.
-Reiser's scan is slightly different.
-.SH "ANSI C STANDARD"
-.I Cpp
-implements most of the ANSI draft standard.
-You should be aware of the following:
-.IP o
-In the draft standard, the \en (backslash-newline)
-character is "invisible" to all processing. In this implementation,
-it is invisible to strings, but acts a "whitespace" (token-delimiter)
-outside of strings. This considerably simplifies error
-message handling.
-.IP o
-The following extensions to C are processed by cpp:
-.nf
-.sp 1
-.ta 4n 27n
- #elif expression (#else #if)
- '\exNNN' (Hexadecimal constants)
- '\ea' (Ascii BELL)
- '\ev' (Ascii VT)
- #if defined NAME (1 if defined, 0 if not)
- #if defined (NAME) (1 if defined, 0 if not)
- unary + (gag me with a spoon)
-.fi
-.IP o
-The draft standard has extended C, adding a string
-concatenation operator, where
-.br
-.nf
- "foo" "bar"
-.fi
-.br
-is regarded as the single string "foobar". It is not clear
-from the draft standard whether this applies to pre-processing
-if macro formals are recognized in strings.
-.SH "ERROR MESSAGES"
-.br
-Many.
-.br
-.SH AUTHOR
-.br
-Martin Minow
-.br
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