If you happen to use popen don't forget to use pclose ... I just spent hours trying to figure out why my oh /not/ so elegantly written code was leaving defunct processes all over the place.

So here's how to do it correctly.

import std.sting;
import std.stream;

extern (C) FILE * popen(char *,char *) ;

int main ()  {
char [] cmd = "ps -A";
FILE * PH;
IN = popen(cmd,"r");
char [] line, tmp_line;
if (!IN) {
//fav error message here
} else {
// read from results
while (fgets(line_tmp,line_tmp.sizeof,IN) ) {
line ~= std.string.chomp(line_tmp);
}
}

if (pclose(IN)!=0 ) {
// error msg here
}
return 0;
}

Hello,

i try to compile your programm, but i get some error message.

<code> import std.string; import std.stream; import std.c.stdio; import std.stdio;

extern (C) FILE* popen(char *,char *); extern (C) int pclose(FILE*);

int main() { char [] cmd = "ps -A"; FILE* IN; IN = popen(cmd,"r");

char [2500] tmp_line; char [] line; if (!IN) { // error message } else { // read from results //while (fgets(tmp_line,tmp_line.sizeof,IN) != null) { while (fgets(tmp_line,tmp_line.sizeof,IN) ) { line ~= std.string.chomp(tmp_line); writefln(line); } }

if ( pclose(IN) !=0 ) { // error message } return 0; }

</code>

I must insert the line "char [2500] tmp_line;" only with "char [] tmp_line" i get segmentaution fault This line too: extern (C) int pclose(FILE*);

My output is: PID TTY          TIME CMD Error: 4invalid UTF-8 sequence

:-(

My system is Debian stable and dmd 139 .


In article <dl2tu1$15ia$1@digitaldaemon.com>, Charles says...
> 
>If you happen to use popen don't forget to use pclose ... I just spent hours trying to figure out why my oh /not/ so elegantly written code was leaving defunct processes all over the place.
> 
>So here's how to do it correctly.
> 
>import std.sting; import std.stream;
> 
>extern (C) FILE * popen(char *,char *) ;
> 
>int main ()  { char [] cmd = "ps -A"; FILE * PH; IN = popen(cmd,"r"); char [] line, tmp_line; if (!IN) { //fav error message here } else { // read from results while (fgets(line_tmp,line_tmp.sizeof,IN) ) { line ~= std.string.chomp(line_tmp); } }
> 
>if (pclose(IN)!=0 ) { // error msg here } return 0; }
> 
> 

someone wrote:
> Hello,   
> 
> i try to compile your programm, but i get some error message.   
> 
> <code>   import std.string;  import std.stream;  import std.c.stdio;  import std.stdio;  
> 
> extern (C) FILE* popen(char *,char *);  extern (C) int pclose(FILE*);  
> 
> int main() {  char [] cmd = "ps -A";  FILE* IN;  IN = popen(cmd,"r");  
> 
> char [2500] tmp_line;  char [] line;  if (!IN) {  // error message  } else {  // read from results  //while (fgets(tmp_line,tmp_line.sizeof,IN) != null) {  while (fgets(tmp_line,tmp_line.sizeof,IN) ) {  line ~= std.string.chomp(tmp_line);  writefln(line);  }  }  
> 
> if ( pclose(IN) !=0 ) {  // error message  }  return 0;  }  
> 
> </code>  
> 
> I must insert the line "char [2500] tmp_line;"  only with "char [] tmp_line" i get segmentaution fault  This line too: extern (C) int pclose(FILE*);  

Many C-functions need a preallocated buffer to store the results.

> My output is:  PID TTY          TIME CMD  Error: 4invalid UTF-8 sequence

The C-functions used here don't support Unicode. Convert the output to UTF or use printf instead.