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F_SETPIPE_SZ uneclared

I have included the following headers:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>

I also tried to use

#define _GNU_SOURCE

before #include <unistd.h>

, but that doesn't help either.

I'm trying to use fcntl

and pass it F_SETPIPE_SZ

as the second argument, but I keep getting this error message:

error: 'F_SETPIPE_SZ uneclared (use in this function first)

I actually found out that I don't need this, but I'm just wondering why I can't use it.

Thank.

So here's the solution, thanks to Chrono Kitsune: Placed

 #define _GNU_SOURCE

before turning on.

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2 answers


So here, thanks to Chrono Kitsune :

Placed

#define _GNU_SOURCE


before turning on.

You should also pay attention to Chrono Kitsune's other comment .

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F_SETPIPE_SZ / F_GETPIPE_SZ are relatively recent. Older kernels (like the 2.6.32 used in RHEL6) do not have them. If you look in /usr/include/linux/fcntl.h and those constants are undefined then this API won't work and you have to find a way around it in what you are building.



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