I have a program which I wish to modify. It used to be run from the command line, but now I wish to change this so it can be used as a function.
The program has complex argument processing so I want to pass my paramters to as if it were being called by the OS as a program.
I have tried to... (2 Replies)
I searched on the forums. No advises.
I am using a previous source code. I changed the main function main(int argc, char **argv) in a function misc(int argc, char **argv). How do you use the argc and argv parameters? This is how I am calling the function :
char param;
strcat(param,"wgrib ");... (4 Replies)
I have a script that asks a bunch of questions using the following method for input:
print "Name:";
while(<>){
chomp;
$name=$_;
}
So for example, if the questions asked for name, age, & color (in that order)... I want to be able to easily convert $ARGV into the input expected by... (2 Replies)
Hi C experts,
I have the following code for adding command line option for a program
int main (argc, argv)
int argc;
char *argv;
{
char *mem_type; //memory type
char *name; //name of the memory
int addr; //address bits
int data; ... (5 Replies)
this is in one of my scripts...
if ($#argv == 0) then
echo 'blah bla'
exit 0
endif
I want it to be something like this...
if ($#argv == 0 OR $argv >=3)
echo 'blah bla'
exit 0
endif
so when the arguments are none, or greater than three I want this "if then" to take over. how? I... (5 Replies)
Hello all,
Had a quick question:
In a typical csh script should inputting via stdin (i.e. set i = $< ) increase the value of $#argv ?
echo enter an value:
set val= "$<"
if($#argv == 0) then
echo No args
else
echo The arg is $argv
so if a value is inputted #argv... (1 Reply)
when i run my program, i have a parameter, that i want to set the value to another string
i am using
int main(int argc, char **argv) {
char my_str=argv;
printf("%s",my_str);
return 0;
}
and i get
Segmentation fault
ran using
./my_prog /usr/share/dict/words hello1
... (2 Replies)
I'm working on my own pow function and I need to make a copy of *argv but
I think that I am having trouble with the size of *argv and the size of any array that I
make. The code below isn't working for me. and I want to accept any number no
matter the size with pow -f 2 2. I was working out... (16 Replies)
All of my machines (various open source derivatives on x86 and amd64) store argv above the stack (at a higher memory address). I am curious to learn if any systems store argv below the stack (at a lower memory address).
I am particularly interested in proprietary Unices, such as Solaris, HP-UX,... (9 Replies)
Discussion started by: alister
9 Replies
LEARN ABOUT REDHAT
apache::subprocess
SUBPROCESS(1) User Contributed Perl Documentation SUBPROCESS(1)NAME
Apache::SubProcess -- Executing SubProcesses from mod_perl
SYNOPSIS
use Apache::SubProcess ();
use Config;
use constant PERLIO_IS_ENABLED => $Config{useperlio};
# pass @ARGV / read from the process
$command = "/tmp/argv.pl";
@argv = qw(foo bar);
$out_fh = Apache::SubProcess::spawn_proc_prog($r, $command, @argv);
$output = read_data($out_fh);
# pass environment / read from the process
$command = "/tmp/env.pl";
$r->subprocess_env->set(foo => "bar");
$out_fh = Apache::SubProcess::spawn_proc_prog($r, $command);
$output = read_data($out_fh);
# write to/read from the process
$command = "/tmp/in_out_err.pl";
($in_fh, $out_fh, $err_fh) =
Apache::SubProcess::spawn_proc_prog($r, $command);
print $in_fh "hello
";
$output = read_data($out_fh);
$error = read_data($err_fh);
# helper function to work w/ and w/o perlio-enabled Perl
sub read_data {
my($fh) = @_;
my $data;
if (PERLIO_IS_ENABLED || IO::Select->new($fh)->can_read(10)) {
$data = <$fh>;
}
return defined $data ? $data : '';
}
DESCRIPTION
"Apache::SubProcess" provides the Perl API for running and communicating with processes spawned from mod_perl handlers.
API
spawn_proc_prog()
$out_fh =
Apache::SubProcess::spawn_proc_prog($r, $command, [@argv]);
($in_fh, $out_fh, $err_fh) =
Apache::SubProcess::spawn_proc_prog($r, $command, [@argv]);
spawn_proc_prog() spawns a sub-process which exec()'s $command and returns the output pipe filehandle in the scalar context, or input, out-
put and error pipe filehandles in the list context. Using these three pipes it's possible to communicate with the spawned process.
The third optional argument is a reference to an array which if passed becomes ARGV to the spawned program.
It's possible to pass environment variables as well, by calling:
$r->subprocess_env->set($key => $value);
before spawning the subprocess.
There is an issue with reading from the read filehandle ($in_fh)):
A pipe filehandle returned under perlio-disabled Perl needs to call select() if the other end is not fast enough to send the data, since
the read is non-blocking.
A pipe filehandle returned under perlio-enabled Perl on the other hand does the select() internally, because it's really a filehandle
opened via ":APR" layer, which internally uses APR to communicate with the pipe. The way APR is implemented Perl's select() cannot be used
with it (mainly because select() wants fileno() and APR is a crossplatform implementation which hides the internal datastructure).
Therefore to write a portable code, you want to use select for perlio-disabled Perl and do nothing for perlio-enabled Perl, hence you can
use something similar to the read_data() wrapper shown in the SYNOPSIS section.
perl v5.8.0 2002-09-02 SUBPROCESS(1)