Platform Type Identification
============================
You can use the `uname' function to find out some information about
the type of computer your program is running on. This function and the
associated data type are declared in the header file `sys/utsname.h'.
As a bonus, `uname' also gives some information identifying the
particular system your program is running on. This is the same
information which you can get with functions targetted to this purpose
described in Note:Host Identification.
- Data Type: struct utsname
The `utsname' structure is used to hold information returned by
the `uname' function. It has the following members:
`char sysname[]'
This is the name of the operating system in use.
`char release[]'
This is the current release level of the operating system
implementation.
`char version[]'
This is the current version level within the release of the
operating system.
`char machine[]'
This is a description of the type of hardware that is in use.
Some systems provide a mechanism to interrogate the kernel
directly for this information. On systems without such a
mechanism, the GNU C library fills in this field based on the
configuration name that was specified when building and
installing the library.
GNU uses a three-part name to describe a system
configuration; the three parts are CPU, MANUFACTURER and
SYSTEM-TYPE, and they are separated with dashes. Any
possible combination of three names is potentially
meaningful, but most such combinations are meaningless in
practice and even the meaningful ones are not necessarily
supported by any particular GNU program.
Since the value in `machine' is supposed to describe just the
hardware, it consists of the first two parts of the
configuration name: `CPU-MANUFACTURER'. For example, it
might be one of these:
`"sparc-sun"', `"i386-ANYTHING"', `"m68k-hp"',
`"m68k-sony"', `"m68k-sun"', `"mips-dec"'
`char nodename[]'
This is the host name of this particular computer. In the
GNU C library, the value is the same as that returned by
`gethostname'; see Note:Host Identification.
gethostname() is implemented with a call to uname().
`char domainname[]'
This is the NIS or YP domain name. It is the same value
returned by `getdomainname'; see Note:Host Identification.
This element is a relatively recent invention and use of it
is not as portable as use of the rest of the structure.
- Function: int uname (struct utsname *INFO)
The `uname' function fills in the structure pointed to by INFO
with information about the operating system and host machine. A
non-negative value indicates that the data was successfully stored.
`-1' as the value indicates an error. The only error possible is
`EFAULT', which we normally don't mention as it is always a
possibility.