gethostname


SYNOPSIS
       #include <unistd.h>

       int gethostname(char *name, size_t len);
       int sethostname(const char *name, size_t len);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       gethostname():
           Since glibc 2.12: _BSD_SOURCE || _XOPEN_SOURCE >= 500
           || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200112L
       sethostname():
           _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

DESCRIPTION
       These  system calls are used to access or to change the hostname of the
       current processor.

       sethostname() sets the hostname to the value  given  in  the  character
       array  name.   The  len argument specifies the number of bytes in name.
       (Thus, name does not require a terminating null byte.)

       gethostname() returns the null-terminated  hostname  in  the  character
       array  name,  which  has a length of len bytes.  If the null-terminated
       hostname is too large to fit, then the name is truncated, and no  error
       is  returned  (but  see  NOTES  below).  POSIX.1-2001 says that if such
       truncation occurs, then it is unspecified whether the  returned  buffer
       includes a terminating null byte.

RETURN VALUE
       On  success,  zero is returned.  On error, -1 is returned, and errno is
       set appropriately.

ERRORS
       EFAULT name is an invalid address.

       EINVAL len is negative or, for sethostname(), len is  larger  than  the
              maximum allowed size.

       ENAMETOOLONG
              (glibc  gethostname())  len  is  smaller  than  the actual size.
              (Before version 2.1, glibc uses EINVAL for this case.)

       EPERM  For sethostname(), the caller did  not  have  the  CAP_SYS_ADMIN
              capability.

CONFORMING TO
       SVr4,   4.4BSD    (these   interfaces   first   appeared   in  4.2BSD).
       POSIX.1-2001 specifies gethostname() but not sethostname().

NOTES
       SUSv2  guarantees  that  "Host  names  are  limited  to   255   bytes".
       POSIX.1-2001 guarantees that "Host names (not including the terminating

       Versions of glibc before 2.2 handle the case where the  length  of  the
       nodename  was  greater  than  or  equal  to len differently: nothing is
       copied into name and the function returns -1 with errno set  to  ENAME-
       TOOLONG.

SEE ALSO
       getdomainname(2), setdomainname(2), uname(2)

COLOPHON
       This  page  is  part of release 3.54 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



Linux                             2010-09-26                    GETHOSTNAME(2)
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