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Old 05-18-2006, 02:11 AM   #1
Thinking
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Registered: Oct 2003
Posts: 249

Rep: Reputation: 30
redirecting stdout to /dev/null and stderr to stdout?


hiho@ll

what i want:
execute another programm within my C app using popen(); and check if an error occured

how i try it:
Code:
FILE *fp = popen("someprog someparams 1>/dev/null 2>&1","r");
if(fp!=NULL){
   int len = fread(buffer,sizeof(char),1024,fp);
   if(len>0){
       printf("WTF: AN ERROR!!!");
       error = true;
   }
   pclose(fp);
}
what i wanted to do:
redirect stdout to dev null and stderr to stdout, so i can read using popen and i only get stderr
just a simple schematic example:
"tar blablabla 1>/dev/null 2>&1" --> i get nothing
"tar blablabla" --> i get the error to stdout i wanted to read from stdin

another possibility would be redirect stderr to a file and check if the file is empty

Q1: any suggestion, how i can do the redirection, so it works? OR how can i read stderr instead of stdout using popen?
Q2: any other option other than creating a file?

thx@ll!

Last edited by Thinking; 05-18-2006 at 02:14 AM.
 
Old 05-18-2006, 02:36 AM   #2
Thinking
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Registered: Oct 2003
Posts: 249

Original Poster
Rep: Reputation: 30
aaarrrgghh
forget about it

system(); returns the exit status of the prog
 
  


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