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Full Discussion: Unclear pointer and array
Top Forums Programming Unclear pointer and array Post 302884218 by yifangt on Saturday 18th of January 2014 02:12:32 PM
Old 01-18-2014
Hi Don!
Your reply confused me more. (It seems a typo for man page for sprintf() instead of printf() function. Right?). Yes, I did look at the man page first. The closest part from the manpage of sprintf is:
Code:
int sprintf(char *str, const char *format, ...);

sprintf(),  snprintf(),  vsprintf()  and vsnprintf() write to the character string str.
 One  can  also specify explicitly which argument is taken, at each place where an argument is required, by writing "%m$" instead of '%' and "*m$" instead of '*', 
where the decimal integer m denotes the position in the argument list of the desired argument, indexed starting from 1.  Thus,
           printf("%*d", width, num);    and     printf("%2$*1$d", width, num);  are equivalent.

Still not clear to me.
For Akshay, I am fine with the pointer moving like src+start. The difficult part is the "%.*s", which is my first time to see it, and I was thinking:
Code:
sprintf(dst, "%.*s", count, src + start);

is equal to:
Code:
sprintf(dst, "%s %d", count, src + start);

Is that right? But Don's line
Code:
sprintf(fmt, "%%.%ds", count);

confused me even more.
The format specification pointers and address with printf() is one of the most difficult part for me. Whenever I saw warning or error msgs like:
Code:
warning: format ‘%c’ expects type ‘int’, but argument 2 has type ‘char *’ [-Wformat]
warning: format ‘%c’ expects type ‘int’, but argument 2 has type ‘size_t *’ [-Wformat] etc.

I panic and bang my head on the table.
Last edited by yifangt; 01-18-2014 at 03:24 PM..
 

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LEARN ABOUT CENTOS

paps

PAPS(1) 						      General Commands Manual							   PAPS(1)

NAME

       paps - UTF-8 to PostScript converter using Pango

SYNOPSIS

       paps [options] files...

DESCRIPTION

       paps reads a UTF-8 encoded file and generates a PostScript language rendering of the file. The rendering is done by creating outline curves
       through the pango ft2 backend.

OPTIONS

       These programs follow the usual GNU command line syntax, with long options starting with  two  dashes  (`-').   A  summary  of  options	is
       included below.

       --landscape
	      Landscape output. Default is portrait.

       --columns=cl
	      Number of columns output. Default is 1.

       --font=desc
	      Set the font description. Default is Monospace 12.

       --rtl  Do rtl layout.

       --paper ps
	      Choose paper size. Known paper sizes are legal, letter, a4. Default is A4.

       --bottom-margin=bm
	      Set bottom margin in postscript points (1/72 inch). Default is 36.

       --top-margin=tm
	      Set top margin. Default is 36.

       --left-margin=lm
	      Set left margin. Default is 36.

       --right-margin=rm
	      Set right margin. Default is 36.

       --help Show summary of options.

       --header
	      Draw page header for each page.

       --markup
	      Interpret the text as pango markup.

       --encoding=ENCODING
	      Assume the documentation encoding is ENCODING.

       --lpi  Set the lines per inch. This determines the line spacing.

       --cpi  Set the characters per inch. This is an alternative method of specifying the font size.

       --stretch-chars
	      Indicates  that  characters  should be stretched in the y-direction to fill up their vertical space. This is similar to the texttops
	      behaviour.

AUTHOR

       paps was written by Dov Grobgeld <dov.grobgeld@gmail.com>.

       This manual page was written by Lior Kaplan <kaplan@debian.org>, for the Debian project (but may be used by others).

								  April  17, 2006							   PAPS(1)
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