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gethostname() - Unix, Linux System Call
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NAME
gethostname, sethostname - get/set host name
SYNOPSIS
#include <unistd.h>
int gethostname(char *name, size_t len);
int sethostname(const char *name, size_t len); DESCRIPTION
These system calls are used to access or to change the host name of the
current processor.
The
gethostname() system call returns a null-terminated hostname (set earlier by
sethostname()) in the array name that has a length of len bytes.
In case the null-terminated hostname does not fit, no error is
returned, but the hostname is truncated. It is unspecified
whether the truncated hostname will be null-terminated.
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and
errno is set appropriately.
ERRORS
Tag | Description |
EFAULT |
name is an invalid address.
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EINVAL |
len is negative or, for
sethostname(), len is larger than the maximum allowed size,
or, for
gethostname() on Linux/i386,
len is smaller than the actual size.
(In this last case glibc 2.1 uses ENAMETOOLONG.)
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EPERM |
For
sethostname(), the caller did not have the
CAP_SYS_ADMIN capability.
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CONFORMING TO
SVr4, 4.4BSD (this 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 null byte) are limited to HOST_NAME_MAX bytes.
GLIBC NOTES
The GNU C library 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. 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
ENAMETOOLONG. SEE ALSO
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