Package: libc5
Version: 5.2.16-1
(My libc5-dev version is also 5.2.16-1)
The following program (which is similar in structure to one of the
programs used in building xlib) loops forever when it reaches EOF on stdin:
#include <stdio.h>
int main(int argc, char **argv)
{
int ksnum,i;
char buf[1024];
long val;
char *c;
printf("EOF is %d\n",EOF);
for (ksnum=0; 1; c=fgets(buf,sizeof(buf),stdin)) {
printf("c is %p\n",c);
i=scanf("#define XK_%s 0x%lx", buf, &val);
printf("i is %d\n",i);
if (i==EOF)
break;
}
printf("Finished.\n");
}
Sample output (running it on its own source code):
myrddin:~/compsci/c$ ./testeof <testeof.c
EOF is -1
c is (nil)
i is 0
c is 0xbffff5c4
i is 0
c is 0xbffff5c4
i is 0
[...]
c is 0xbffff5c4
i is 0
c is 0xbffff5c4
i is 0
c is (nil)
i is 0
[the next two lines...]
c is (nil)
i is 0
[...are repeated forever]
Two things are strange: the first call to fgets() returns nil, and calls
to scanf() once end-of-file has been reached return 0 rather than EOF (-1).
This worked under libc5-5.2.9-2. I noticed because it made my X build
hang; this had never happened before.
The man page for scanf says:
RETURN VALUES
These functions return the number of input items assigned,
which can be fewer than provided for, or even zero, in the
event of a matching failure. Zero indicates that, while
there was input available, no conversions were assigned;
typically this is due to an invalid input character, such
as an alphabetic character for a `%d' conversion. The
value EOF is returned if an input failure occurs before
any conversion such as an end-of-file occurs. If an error
or end-of-file occurs after conversion has begun, the num-
ber of conversions which were successfully completed is
returned.
The man page for fgets() says:
gets() and fgets() return s on success, and NULL on end of
file or error.
Steve Early
[EMAIL PROTECTED]
