Path: utzoo!attcan!uunet!zephyr.ens.tek.com!tekcrl!tekgvs!toma
From: toma@tekgvs.LABS.TEK.COM (Tom Almy)
Newsgroups: comp.sys.ibm.pc
Subject: Re: File concatenation using Microsoft C under MS-DOS?
Message-ID: <7641@tekgvs.LABS.TEK.COM>
Date: 11 Jun 90 15:24:10 GMT
References: <4891@druco.ATT.COM>
Reply-To: toma@tekgvs.LABS.TEK.COM (Tom Almy)
Organization: Tektronix, Inc., Beaverton,  OR.
Lines: 32


[The question was how to concatenate files in the fastest manner].

Assuming you want to use stdio calls (using open, read, and write would be
fastest) do this

FILE *infile, *outfile;
#define BUFSIZE 32768 /* or some other large multiple of 512 */
char *cbuf;
int count;

infile = fopen(sourceFileName,"rb");	/* open in binary mode */
outfile = fopen(concatFileName,"ab");	/* same for destination file */
setbuf(infile,NULL);			/* Do your own buffering */
setbuf(outfile,NULL);
cbuf = malloc(BUFSIZE);

while ((count = fread(cbuf,sizeof(char),BUFSIZE,infile)) > 0)
	fwrite(cbuf,sizeof(char),count,outfile);

free(cbuf);
fclose(infile);
fclose(outfile);


It is important to both specify binary mode (to eliminate the crlf <-> \n
translation) and to use a large buffer, which is in turn better done by
yourself so a single buffer can be used.

Tom Almy
toma@tekgvs.labs.tek.com
Standard Disclaimers Apply