Thread: Checking output stream in C

i trying write c program determine whether program's output tied terminal or redirected other file descriptor.

thought of comparing fileno(stdout) stdout_fileno, not work in case of redirection, of redirections handled dup2.

more clear, want is, say, if run program in terminal, print:

code:

hello world

but if redirect file, write file:

code:

hello world

i know can done, can't find out how. appreciated.

looks ubuntu forum lucky place, got answer after posting this. can checked isatty() function:

code:

#include <unistd.h> #include <stdio.h>  int main() {         if(isatty(fileno(stdout))) printf("yes\n");         else printf("no\n");         return 0; }

here how runs:

code:

zobayer@zobayer:~/lab/system/ls$ g++ test.cpp zobayer@zobayer:~/lab/system/ls$ ./a.out yes zobayer@zobayer:~/lab/system/ls$ ./a.out > out.txt zobayer@zobayer:~/lab/system/ls$ cat out.txt no zobayer@zobayer:~/lab/system/ls$

visit http://linux.die.net/man/3/isatty know isatty() or write in terminal: man 3 isatty

hope helpful if looks in future.

Forum The Ubuntu Forum Community Ubuntu Specialised Support Development & Programming Programming Talk [SOLVED] Checking output stream in C

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