NAME

xt_ff_ungetc() - Put a character back into a fast file stream read buffer

LIBRARY

#include <xtend/fast-file.h>
-lxtend

SYNOPSIS

int     xt_ff_ungetc(xt_ff_t *stream, int ch)

ARGUMENTS

ch      Character to return to the input buffer
stream  Pointer to an xt_ff_t object opened by xt_ff_open(3)

DESCRIPTION

xt_ff_ungetc(3) returns a single character read by xt_ff_getc(3) to the input buffer of a stream opened by xt_ff_open(3). All characters from the most recently read block plus a maximum of XT_FAST_FILE_UNGETC_MAX characters from the previously read block may be returned.

The xt_ff_t system is simpler than and much faster than traditional FILE on typical systems. It is intended for processing large files character-by-character, where low-level block I/O is not convenient, but FILE I/O causes a bottleneck.

RETURN VALUES

The character written, or EOF if unable to write

EXAMPLES

char    *infilename;
xt_ff_t *instream;
int     ch;
if ( (instream = xt_ff_open(infilename, O_RDONLY)) == NULL )
{


    fprintf(stderr, "Cannot open %s for reading: %s.n",


            infilename, strerror(errno));


    exit(EX_NOINPUT);
}
if ( (ch = xt_ff_getc(instream)) != MY_FAVORITE_CHAR )


    xt_ff_ungetc(ch, instream);
xt_ff_close(instream);