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sf_file(3)		 BSD Library Functions Manual		    sf_file(3)

NAME
     initfdpos,	initFILEpos, adjfdpos, adjFILEpos -- file positions indicator
     handling

SYNOPSIS
     #include <stdio.h>
     #include <strfunc.h>

     int
     initfdpos(const char *fname, int stream, const char *ext);

     int
     initFILEpos(const char *fname, FILE *stream, const	char *ext);

     int
     adjfdpos(int stream, int posfd, int doSync);

     int
     adjFILEpos(FILE *stream, int posfd, int doSync);

DESCRIPTION
     Those functions are used to maintain a file positions indicator between
     the program sessions. This	is often needed	when a process is being	parsed
     a log file	and tries to save current position within this log to start
     from this point later.

     int initfdpos(const char *fname, int stream, const	char *ext) creates a
     position indicator	file "<fname>.<ext>", and returns its file descriptor.
     If	the position file is already exists, then it advances stream's posi-
     tion according to the information derived from that file.	initfdpos also
     checks the	file size and inode changes in order to	be robust in situa-
     tions when	file shrinked or replaced.

     int initFILEpos() is almost the same except that it takes a FILE *	argu-
     ment instead of plain file	descriptor.

     Both functions returns position file descriptor, or -1 in case of fail-
     ure.

     int adjfdpos(int stream, int posfd, int doSync) and adFILEdpos() writes
     the current position within the file referenced by	stream into the	posfd.
     If	doSync is not zero, it also does fsync(2).

     Return values: 0 (Success)	or -1 in case of any errors.

EXAMPLE
     void main() {
	     int posfd;
	     FILE *logfile;
	     char buf[1042];

	     logfile = fopen("file.log", "r");
	     if(!logfile)
		     exit(EX_NOINPUT);

	     while(fgets(buf, sizeof(buf), logfile)) {
		     /*	Do something ... */

		     adjFILEpos(logfile, posfd,	0);
	     };

	     /*	Force data to be flushed on disk. */
	     adjFILEpos(logfile, posfd,	1);
	     fclose(logfile);
	     close(posfd);
     };

SEE ALSO
     strfunc(3).

AUTHORS
     Lev Walkin	<vlm@lionet.info>

BSD			       December	4, 2000				   BSD
NAME | SYNOPSIS | DESCRIPTION | EXAMPLE | SEE ALSO | AUTHORS

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