gethostname man page on ElementaryOS

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GETHOSTNAME(2)		   Linux Programmer's Manual		GETHOSTNAME(2)

       gethostname, sethostname - get/set hostname

       #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)):

	   Since glibc 2.12: _BSD_SOURCE || _XOPEN_SOURCE >= 500
	   || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200112L

       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.

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

       EFAULT name is an invalid address.

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

	      (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

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

       SUSv2  guarantees  that	"Host  names  are  limited  to	 255   bytes".
       POSIX.1-2001 guarantees that "Host names (not including the terminating
       null  byte)  are	 limited   to	HOST_NAME_MAX	bytes".	   On	Linux,
       HOST_NAME_MAX  is  defined  with the value 64, which has been the limit
       since Linux 1.0 (earlier kernels imposed a limit of 8 bytes).

   Glibc notes
       The GNU C library  does	not  employ  the  gethostname()	 system	 call;
       instead,	 it  implements gethostname() as a library function that calls
       uname(2) and copies up to len bytes from the  returned  nodename	 field
       into  name.  Having performed the copy, the function then checks if the
       length of the nodename was greater than or equal to len, and if it  is,
       then  the  function  returns -1 with errno set to ENAMETOOLONG; in this
       case, a terminating null byte is not included in the returned name.

       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	ENAMEā€

       getdomainname(2), setdomainname(2), uname(2)

       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

Linux				  2010-09-26			GETHOSTNAME(2)

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