EOF

[Dave]

Hello NG,

Is EOF an actual character with an ASCII code, or is it an implicit
character?

Thanks,
Dave

 

[Ioannis Vranos]

Dave wrote
:

Hello NG,

Is EOF an actual character with an ASCII code, or is it an implicit
character?

No it is not part of ASCII code, it is a convention, the numeric value
returned/accepted by functions indicating that the end of a file is reached.


It is usually -1.

 

[Gianni Mariani]

Hello NG,

Is EOF an actual character with an ASCII code, or is it an implicit
character?

That is system dependant.

I think most modern system now indicate eof when there is no more data
to be read.

Earlier systems (like cpm and msdos) had a ^Z character to indicate end
of file.

 

[Artie Gold]

Dave wrote
:




No it is not part of ASCII code, it is a convention, the numeric value
returned/accepted by functions indicating that the end of a file is
reached.


It is usually -1.

And it's an *int*!

HTH,
--ag

 

[Thomas Matthews]

Hello NG,

Is EOF an actual character with an ASCII code, or is it an implicit
character?

Thanks,
Dave

EOF is not part of the ASCII code, it is a value that
is outside the range of a character, which is why functions
that return EOF return an int, not a char.

--
Thomas Matthews

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http://www.josuttis.com -- C++ STL Library book
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[David Harmon]

On Sun, 23 Jan 2005 12:38:51 -0800 in comp.lang.c++, Gianni Mariani

Earlier systems (like cpm and msdos) had a ^Z character to indicate end
of file.

And all the way to current MS Windows systems. Likewise ^D indicates
end of file in some Unix contexts. However, that has no relation to
the C and/or C++ standard #define EOF

EOF is a special value returned from fgetc() etc. that specifically is
outside the range of values of a char.

 

[Jonathan Turkanis]

On Sun, 23 Jan 2005 12:38:51 -0800 in comp.lang.c++, Gianni Mariani


And all the way to current MS Windows systems. Likewise ^D indicates
end of file in some Unix contexts. However, that has no relation to
the C and/or C++ standard #define EOF

EOF is a special value returned from fgetc() etc. that specifically is
outside the range of values of a char.

It's also the return value of char_traits<char>::eof(), and as such plays an
important (but not very exciting) role in the C++ iostreams framework.

Jonathan

 

[Rolf Magnus]

EOF is a special value returned from fgetc() etc. that specifically is
outside the range of values of a char.

It usually is, but that's not required. On a platform where int and char
have the same size, it wouldn't be possible to find an int value that is
not also a valid value for a char. That's why there is also the function
feof().

 

[Niels Dybdahl]

Earlier systems (like cpm and msdos) had a ^Z character to indicate end

And all the way to current MS Windows systems. Likewise ^D indicates
end of file in some Unix contexts. However, that has no relation to
the C and/or C++ standard #define EOF

It does have a relation, because some compilers generate an EOF when ^D or
^Z is encountered. The ASCII name for ^D is "End of transmission" and is
also used for indicating end of file on Macs.

Niels Dybdahl

 

[Niels Dybdahl]

Earlier systems (like cpm and msdos) had a ^Z character to indicate end

And all the way to current MS Windows systems. Likewise ^D indicates
end of file in some Unix contexts. However, that has no relation to
the C and/or C++ standard #define EOF

It does have a relation, because some compilers generate an EOF when ^D or
^Z is encountered. The ASCII name for ^D is "End of transmission" and is
also used for indicating end of file on Macs.

Niels Dybdahl

 

[Niels Dybdahl]

Earlier systems (like cpm and msdos) had a ^Z character to indicate end

And all the way to current MS Windows systems. Likewise ^D indicates
end of file in some Unix contexts. However, that has no relation to
the C and/or C++ standard #define EOF

It does have a relation, because some compilers generate an EOF when ^D or
^Z is encountered. The ASCII name for ^D is "End of transmission" and is
also used for indicating end of file on Macs.

Niels Dybdahl