Implement concat() using read(2) and write(2)

This forces the data to be read as soon as they are available
and a simple cat(1) when stdin is referring to a tty works as
expected.
This commit is contained in:
sin 2014-11-13 14:14:20 +00:00
parent a8c31586c5
commit 5773a8f22b

View File

@ -1,5 +1,6 @@
/* See LICENSE file for copyright and license details. */ /* See LICENSE file for copyright and license details. */
#include <stdio.h> #include <stdio.h>
#include <unistd.h>
#include "../text.h" #include "../text.h"
#include "../util.h" #include "../util.h"
@ -8,14 +9,12 @@ void
concat(FILE *fp1, const char *s1, FILE *fp2, const char *s2) concat(FILE *fp1, const char *s1, FILE *fp2, const char *s2)
{ {
char buf[BUFSIZ]; char buf[BUFSIZ];
size_t n; ssize_t n;
while ((n = fread(buf, 1, sizeof buf, fp1)) > 0) { while ((n = read(fileno(fp1), buf, sizeof buf)) > 0) {
if (fwrite(buf, 1, n, fp2) != n) if (write(fileno(fp2), buf, n) != n)
eprintf("%s: write error:", s2); eprintf("%s: write error:", s2);
if (feof(fp1))
break;
} }
if (ferror(fp1)) if (n < 0)
eprintf("%s: read error:", s1); eprintf("%s: read error:", s1);
} }