Serial port

B

BartC

I'd been looking for a standalone Windows (7) executable to monitor a serial
port, but thought I'd try the following code, and it worked!

This is not exactly a C problem but perhaps someone might know why fgetc()
mostly returns -1 (EOF), presumably when no character is ready, rather than
wait until one is available (as it might do for f==stdin). As it is, it ties
up the processor, so can't be used seriously.

#include <stdio.h>
#include <stdlib.h>

int main (void) {
FILE* f;
int c;

f=fopen("com3","r");

if (!f) exit(0);

while (1) {
c=fgetc(f);
if (c!=EOF) printf("%c",c);
}
}
 
J

James Kuyper

I'd been looking for a standalone Windows (7) executable to monitor a serial
port, but thought I'd try the following code, and it worked!

This is not exactly a C problem ...
Correct.

... but perhaps someone might know why fgetc()
mostly returns -1 (EOF), presumably when no character is ready, rather than
wait until one is available (as it might do for f==stdin). ...

Almost certainly true - but did you really think you were more likely to
find such a person here, rather than in a forum associated with Windows?
 
K

Kenny McCormack

I'd been looking for a standalone Windows (7) executable to monitor a serial
port, but thought I'd try the following code, and it worked!

A million or so years ago, I used a program called DSZ to do exactly this.
It still works to this day.

I could probably shoot you a binary if you are interested.

--
"They shall be attended by boys graced with eternal youth, who to the
beholder?s eyes will seem like sprinkled pearls. When you gaze upon that
scene, you will behold a kingdom blissful and glorious."

--- Qur'an 76:19 ---
 
L

Les Cargill

BartC said:
I'd been looking for a standalone Windows (7) executable to monitor a
serial
port, but thought I'd try the following code, and it worked!

This is not exactly a C problem but perhaps someone might know why fgetc()
mostly returns -1 (EOF), presumably when no character is ready, rather than
wait until one is available (as it might do for f==stdin). As it is, it
ties
up the processor, so can't be used seriously.

#include <stdio.h>
#include <stdlib.h>

int main (void) {
FILE* f;
int c;

f=fopen("com3","r");

if (!f) exit(0);

while (1) {
c=fgetc(f);
if (c!=EOF) printf("%c",c);
}
}


I use PuTTY for this purpose:

http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
 

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