Correct way to read data of different formats into same struct Post: 302940706

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Top Forums Programming Correct way to read data of different formats into same struct Post 302940706 by yifangt on Wednesday 8th of April 2015 12:19:29 PM

04-08-2015

Registered User

I panic when I saw those phrases:

Quote:

is dangerous in many ways, doesn't do precisely what you want(%s stops at first whitespace) and has no good options for error-checking.

A solid understanding of the functions fscanf(), sscanf(), fgets() is needed to use them properly.
Use fgets and sscanf like I keep telling youI was trying to understand why, and before that, I need catch how "flow of the data" (sometime I think it as stream) was read into memory, or handled by the program. RS/FS was borrowed to show my understanding as awk handle formatted data with these two VAR, which is not appropriate here apparently. So many options, I need understand the right choice. This part is hard at my first sight to Read three lines into the same buffer

Code:

                // Read three lines into the same buffer.
                if(!fgets(buf, 4096-bpos, stdin)) break;          //To help my understanding, can I do this, as bpos is set 0 before the loop?
                bpos = strlen(buf);                               // could be more efficient but you get the idea
                if(!fgets(buf+bpos, 4096-bpos, stdin)) break;
                bpos = strlen(buf);
                if(!fgets(buf+bpos, 4096-bpos, stdin)) break;

Thanks a lot!

Last edited by yifangt; 04-08-2015 at 01:34 PM..

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explain_fgets_or_die

explain_fgets_or_die(3) 				     Library Functions Manual					   explain_fgets_or_die(3)

NAME

       explain_fgets_or_die - input of strings and report errors

SYNOPSIS

       #include <libexplain/fgets.h>
       char *explain_fgets_or_die(char *data, int data_size, FILE *fp);

DESCRIPTION

       The  explain_fgets_or_die function is used to call the fgets(3) system call.  On failure an explanation will be printed to stderr, obtained
       from explain_fgets(3), and then the process terminates by calling exit(EXIT_FAILURE).

       This function is intended to be used in a fashion similar to the following example:
	      explain_fgets_or_die(data, data_size, fp);

       data    The data, exactly as to be passed to the fgets(3) system call.

       data_size
	       The data_size, exactly as to be passed to the fgets(3) system call.

       fp      The fp, exactly as to be passed to the fgets(3) system call.

       Returns:
	       This function only returns on success; data when a line is read, or NULL on end-of-file.  On failure,  prints  an  explanation  and
	       exits.

SEE ALSO

       fgets(3)
	       input of strings

       explain_fgets(3)
	       explain fgets(3) errors

       exit(2) terminate the calling process

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2008 Peter Miller

															   explain_fgets_or_die(3)

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