R devel - Sep 2004 - bitmap() doesn't finish with file in Windows (PR#7224)

Full_Name: Tom Short
Version: 1.9.0
OS: Win2000 
Submission from: (NULL) (64.65.255.41)


POSSIBLE WISHLIST, POSSIBLE BUG:

The following code works on Debian, but fails on Windows 2000 with 'Error in
file("test.png", "r") : unable to open connection':

bitmap("test.png")
plot(c(1,2,3))
dev.off()
x = file("test.png","r")

The problem is that when bitmap uses ghostscript to convert the PS file to a
PNG, the postscript drive doesn't wait for ghostscript to finish (under
Windows). In the Linux version, the postscript driver does wait for the printing
command to finish. Compare the following lines of devPS.c that actually call the
"cmd":

#ifdef Unix
	    err = R_system(buff);
#endif
#ifdef Win32
	    err = runcmd(buff, 0, 0, NULL);
#endif

RECOMMENDATION: Change runcmd(buff, 0, 0, NULL) to runcmd(buff, 1, 0, NULL) in
devPS.c to make the driver wait for the command to finish.

This is deliberate, as processing can take a long time and we don't
want to lock R whilst a printer prints a file for example.

Just insert a sleep(1).

It certainly is not a bug, as no one said you would be able to access a 
file immediately.

On Mon, 13 Sep 2004 t.short@epri-peac.com wrote:
> Full_Name: Tom Short
> Version: 1.9.0
> OS: Win2000 
> Submission from: (NULL) (64.65.255.41)
> 
> 
> POSSIBLE WISHLIST, POSSIBLE BUG:
> 
> The following code works on Debian, but fails on Windows 2000 with
'Error in
> file("test.png", "r") : unable to open connection':
> 
> bitmap("test.png")
> plot(c(1,2,3))
> dev.off()
> x = file("test.png","r")
> 
> The problem is that when bitmap uses ghostscript to convert the PS file to
a
> PNG, the postscript drive doesn't wait for ghostscript to finish (under
> Windows). In the Linux version, the postscript driver does wait for the
printing
> command to finish. Compare the following lines of devPS.c that actually
call the
> "cmd":
> 
> #ifdef Unix
> 	    err = R_system(buff);
> #endif
> #ifdef Win32
> 	    err = runcmd(buff, 0, 0, NULL);
> #endif
> 
> RECOMMENDATION: Change runcmd(buff, 0, 0, NULL) to runcmd(buff, 1, 0, NULL)
in
> devPS.c to make the driver wait for the command to finish.
> 
> ______________________________________________
> R-devel@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
> 
-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595