Content-type: text/html Man page of unifdef

unifdef

Section: User Commands (1)
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NAME

unifdef - Removes #ifdefed lines  

SYNOPSIS

unifdef [-tlc] [-Dsymbol] [-idsymbol] [-iusymbol] [file] [-Usymbol]

The unifdef command partially simulates the behavior of the C preprocessor in processing #ifdef conditionals.
 

OPTIONS

Complements the action of unifdef; retains lines that would normally be removed and removes lines that would normally be retained. Specifies symbol as a defined #ifdef symbol. Specifies defined lines inside certain #ifdefs to be ignored but copied out. Specifies undefined lines inside certain #ifdefs to be ignored and not copied out. Replaces removed lines with blank lines instead of deleting them. Processes plain text (rather than C code) input. The unifdef command does not try to recognize comments, single quotes, and double quotes. Specifies symbol as an undefined #ifdef symbol.
 

DESCRIPTION

The unifdef command recognizes nested #ifdefs, comments, single and double quotes of C syntax so that it can function correctly, but does not include files or interpret macros. The unifdef command recognizes, but does not remove comments.

The unifdef command takes its input from stdin if no file argument is given, and copies its output to stdout.

You specify the symbols you want defined with -Dsymbol or undefined with -Usymbol and the lines inside those #ifdefs are copied to the output or removed, as appropriate. The #ifdef, #ifndef, #else, #elif, and endif lines associated with symbol are also removed. The #ifdefs involving unspecified symbols are untouched and copied out along with their associated #ifdef, #else, elif, and #endif lines. If the same symbol appears in more than one argument, only the first occurrence is significant. For instance, if an #ifdef X occurs nested inside another #ifdef X, the inside #ifdef is considered an unrecognized symbol.

If you use #ifdefs to delimit non-C lines, such as comments or unfinished code, it is necessary to specify which symbols are to be used for that purpose. Otherwise, the unifdef command tries to parse for quotes and comments in those #ifdef lines.
 

Keywords

The following keywords can be used with the unifdef command:

ifdef ifndef else endif elif

The unifdef command uses the elif keyword as follows. (Note that ``Understood'' means unifdef knows how to convert elif to if.) Understood Not understood Not understood

For example:

# ifdef X x # elif defined (Y) y # elif defined (A) || defined (B) a # else default # endif

The following list shows the results of using the elif keyword with variables:

-DX x

-UX # if defined (Y) y # elif defined (A) || defined (B) a # else default # endif -UX -DY y

-UY -UX # if defined (Y) y # elif defined (A) || defined (B) a # else default # endif

-UY -UX -DA # if defined (Y) y # elif defined (A) || defined (B) a # else default # endif


 

NOTES

The unifdef command cannot process cpp constructs such as:

#if defined(X) || defined(Y)


 

DIAGNOSTICS

The unifdef command can fail for several reasons: a premature end of file, or an inappropriate else, elif, or endif.
 

EXIT STATUS

Exit status is 0 if output is an exact copy of input, 1 if not, 2 if the unifdef command fails.
 

EXAMPLES

The following command line causes the unifdef command to read the file original.c and remove the #ifdef A lines. It then removes everything following an #elif/#else associated with the #ifdef A down to the #endif: unifdef -DA original.c > modified.c The following command line causes the unifdef command to read the file original.c, and remove the #ifdef A down to either its associated #elif/#else, or its associated #endif: unifdef -UA original.c > modified.c

In the case of the #elif, the #elif is replaced with #if. In the case of #else, the #else is deleted along with its associated #endif.
 

SEE ALSO

Commands:  diff(1)


 

Index

NAME
SYNOPSIS
OPTIONS
DESCRIPTION
Keywords
NOTES
DIAGNOSTICS
EXIT STATUS
EXAMPLES
SEE ALSO

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Time: 02:42:59 GMT, October 02, 2010