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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | VERSIONS | NOTES | STANDARDS | SEE ALSO | COLOPHON |
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bindresvport(3) Library Functions Manual bindresvport(3)
bindresvport - bind a socket to a privileged IP port
Standard C library (libc, -lc)
#include <sys/types.h>
#include <netinet/in.h>
int bindresvport(int sockfd, struct sockaddr_in *sin);
bindresvport() is used to bind the socket referred to by the file
descriptor sockfd to a privileged anonymous IP port, that is, a
port number arbitrarily selected from the range 512 to 1023.
If the bind(2) performed by bindresvport() is successful, and sin
is not NULL, then sin->sin_port returns the port number actually
allocated.
sin can be NULL, in which case sin->sin_family is implicitly taken
to be AF_INET. However, in this case, bindresvport() has no way
to return the port number actually allocated. (This information
can later be obtained using getsockname(2).)
bindresvport() returns 0 on success; otherwise -1 is returned and
errno is set to indicate the error.
bindresvport() can fail for any of the same reasons as bind(2).
In addition, the following errors may occur:
EACCES The calling process was not privileged (on Linux: the
calling process did not have the CAP_NET_BIND_SERVICE
capability in the user namespace governing its network
namespace).
EADDRINUSE
All privileged ports are in use.
EAFNOSUPPORT (EPFNOSUPPORT in glibc 2.7 and earlier)
sin is not NULL and sin->sin_family is not AF_INET.
For an explanation of the terms used in this section, see
attributes(7).
┌────────────────┬───────────────┬───────────────────────────────┐
│ Interface │ Attribute │ Value │
├────────────────┼───────────────┼───────────────────────────────┤
│ bindresvport() │ Thread safety │ glibc >= 2.17: MT-Safe; │
│ │ │ glibc < 2.17: MT-Unsafe │
└────────────────┴───────────────┴───────────────────────────────┘
The bindresvport() function uses a static variable that was not
protected by a lock before glibc 2.17, rendering the function MT-
Unsafe.
Present on the BSDs, Solaris, and many other systems.
Unlike some bindresvport() implementations, the glibc
implementation ignores any value that the caller supplies in
sin->sin_port.
BSD.
bind(2), getsockname(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-6.10.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-02-02. 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 6.10 2024-07-23 bindresvport(3)
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HTML rendering created 2025-02-02 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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