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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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F_GETPIPE_SZ(2const) F_GETPIPE_SZ(2const)
F_GETPIPE_SZ, F_SETPIPE_SZ - get/set the capacity of a pipe
Standard C library (libc, -lc)
#define _GNU_SOURCE
#include <fcntl.h>
int fcntl(int fd, F_SETPIPE_SZ, int arg);
int fcntl(int fd, F_GETPIPE_SZ);
F_SETPIPE_SZ
Change the capacity of the pipe referred to by fd to be at
least arg bytes. An unprivileged process can adjust the
pipe capacity to any value between the system page size and
the limit defined in /proc/sys/fs/pipe-max-size (see
proc_sys_fs(5)). Attempts to set the pipe capacity below
the page size are silently rounded up to the page size.
Attempts by an unprivileged process to set the pipe
capacity above the limit in /proc/sys/fs/pipe-max-size
yield the error EPERM; a privileged process
(CAP_SYS_RESOURCE) can override the limit.
When allocating the buffer for the pipe, the kernel may use
a capacity larger than arg, if that is convenient for the
implementation. (In the current implementation, the
allocation is the next higher power-of-two page-size
multiple of the requested size.) The actual capacity (in
bytes) that is set is returned as the function result.
Attempting to set the pipe capacity smaller than the amount
of buffer space currently used to store data produces the
error EBUSY.
Note that because of the way the pages of the pipe buffer
are employed when data is written to the pipe, the number
of bytes that can be written may be less than the nominal
size, depending on the size of the writes.
F_GETPIPE_SZ
Return (as the function result) the capacity of the pipe
referred to by fd.
The pipe capacity.
On error, -1 is returned, and errno is set to indicate the error.
See fcntl(2).
EBUSY op is F_SETPIPE_SZ and the new pipe capacity specified in
arg is smaller than the amount of buffer space currently
used to store data in the pipe.
EPERM op is F_SETPIPE_SZ and the soft or hard user pipe limit has
been reached; see pipe(7).
Linux.
Linux 2.6.35.
fcntl(2)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-07-20 F_GETPIPE_SZ(2const)
Pages that refer to this page: fcntl(2)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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