Ok, tried some other stuff, see test code below. When the counter 'i' reaches
128 (* 8 = 1024 files opened and closed) i get bad printouts from the open and
read calls.
My test code:
(panna.c)
#include <stdio.h>
#include <fcntl.h>
void msDelay(int ms)
{
int i,a;
int delayvar=10;
for (a=0;a<ms;a++)
{
for (i=0;i<33084;i++)
{
delayvar*=2;
delayvar/=2;
}
}
}
float readtemp(char* pin)
{
int fil;
char filename[100];
float tot = 0, high = 0, temp, dc;
char c;
sprintf(filename, "/proc/diskstats");
fil = open(filename, O_RDONLY);
if(fil < 0) printf("Open error!");
if(read(fil, &c, 1) != 1) printf("Read error!");
if(tot == 0)
{
return 0;
}
dc = high/tot;
temp = (dc - 0.32) / 0.0047;
close(fil);
return temp;
}
int main(void)
{
//printf("\x1B[1;0;0;10;31;14;4;0;0Q");
//printf("\x1B[2J\x1B[4;8H=)\x1B[2;3HJonas \x01 Emma");
float temp[8];
char* pins[8] = {"PG01", "PG02", "PG03", "PG04", "PG05", "PG16",
"PG17", "PG18"};
int i, j = 0;
printf("\x1B[2J"); //ClrScr
while(1)
{
for(i = 0; i <= 7; i++)
{
temp[i] = readtemp(pins[i]);
}
j++;
printf("\x1B[0;0H"); //GotoXY 0,0
printf(" %02.0f %02.0f %02.0f %02.0f %02.0f\n", temp[0],
temp[1], temp[2], temp[3], temp[4]);
printf(" %02.0f %02.0f %04.1f\n", temp[5], temp[6], temp[7]);
printf(" %d", j);
fflush(stdout);
msDelay(10);
}
return 0;
}
Makefile:
AXIS_USABLE_LIBS = UCLIBC GLIBC
include $(AXIS_TOP_DIR)/tools/build/Rules.axis
PROGS = panna
all: $(PROGS)
$(PROGS): $(PROGS).o
$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@
clean:
rm -f $(PROGS) *.o core
Best regards, Jonas
--- In [email protected], j...@... wrote:
>
> on proc you should use open() close() read()
>
> please post the complete code
>
>
>
>
> Quoting "jonas.elofsson" <jelofs...@...>:
>
> > Hi!
> >
> > I have a problem reading files in the /proc directory in C.
> >
> > I made a module for reading SMARTTEMP temperature sensors, and it
> > works great. I made it to create one file for each I/O pin under
> > /proc/smarttemp/. Working beautifully.
> >
> > I also made a module for controlling my LCD display, and that to
> > works like a charm.
> >
> > I put together a small test program to read 8 different temperaturs
> > from different sensors and then display them on the display updating
> > once every second.
> >
> > Works great, for two minutes...
> >
> > Then, when one of the /proc files is read for the 1024:th time
> > problems occurs. It turns out the file descriptors are out..! They
> > don't seem to get relesaed when I do a fclose (I use fopen and
> > fclose on them, is this a problem?).
> >
> > I get no problems if I change the program to read from a file on the
> > normal FS instead.
> >
> > If I try to read some other file in /proc i get the same error after
> > 1024 loops... So it seems it's not in my driver code.
> >
> > I tried to do a system("cp /proc/smarrtemp/PG01 /var/temp"); for
> > each measurement and then reading the file in /var instead, trying
> > to fool it a bit, just for testing. But after about 1024 copies I
> > still get problems.
> >
> > I would be very thankful for any ideas about why this is and how to
> > get it working.
> >
> > I use the image on ACMEs homepage, 2.6 something. =)
> >
> > Best regards, Jonas
> >
> >
> >
> >
>
>
>
> --
> John Crispin
> hacking, coding, etc
> blogic on irc
>
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