hi,
i need to store a value to a particular memory location without having
a variable.
So, how can i access a 'memory address' without using variables??
Is it possible in C???
Plz, help me..
Thanks in advance
Sethu
20  2854  se*****@gmail.c om wrote:
i need to store a value to a particular memory location without having
a variable.
Why?
If you mean that you want to write to an address in your machine that
you only have the numerical form of, then you can't portably do
that in standard C; you'll have to use an implementation extension.
So, how can i access a 'memory address' without using variables??
That depends on what you mean by a "variable". (No, I'm being serious.
Do you count an expression like `*p` a variable?)
Is it possible in C???
Can't tell from your description.
--
Chris ".enable proofreading" Dollin
"A facility for quotation covers the absence of original thought." /Gaudy Night/ se*****@gmail.c om said:
hi,
i need to store a value to a particular memory location without having
a variable.
So, how can i access a 'memory address' without using variables??
Is it possible in C???
That isn't really the question. The questions are:
1) is it possible on all your target platforms?
2) would this value have the same semantics on all those platforms?
If the answer to either of those questions is "no", C can't help you wave a
magic wand to make it so.
If you're using a protected-mode operating system such as Windows or Unix,
it's generally not possible (unless you're way down in the system, or
unless you're using a real-mode emulator of some kind).
If you're using a real-mode system such as MS-DOS or CP/M, it may be
possible.
As for semantics, that's unlikely to be portable across all your target
platforms unless they are extremely similar or unless you only have one
target platform.
Given all that, you can do this in C (but the outcome is not defined by the
C language - C gives you the power to do things like this, but on your own
head be it!):
*(unsigned char *)0xB8000000UL = 65;
On an appropriate system, this writes the letter 'A' on the screen in the
upper left hand corner. On a not-so-appropriate system, it may well crash
your machine. Caveat programmer!
--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999 http://www.cpax.org.uk
email: normal service will be restored as soon as possible. Please do not
adjust your email clients.
In article <11************ **********@f16g 2000cwb.googleg roups.com>,
<se*****@gmail. comwrote:
>i need to store a value to a particular memory location without having
a variable.
That sounds like a class assignment.
>So, how can i access a 'memory address' without using variables??
>Is it possible in C???
I'm not sure if you are asking about pointers, or if you are asking
how to store a value at a particular address location without having
to go through a lot of steps to create a variable that the linker will
happen to put at the desired location ?
--
Programming is what happens while you're busy making other plans.
Walter Roberson wrote:
In article <11************ **********@f16g 2000cwb.googleg roups.com>,
<se*****@gmail. comwrote:
i need to store a value to a particular memory location without having
a variable.
That sounds like a class assignment.
So, how can i access a 'memory address' without using variables??
Is it possible in C???
I'm not sure if you are asking about pointers, or if you are asking
how to store a value at a particular address location without having
to go through a lot of steps to create a variable that the linker will
happen to put at the desired location ?
no, the pointer itself pointing a memory location.
My question is,
char c;
when the compiler reads the above instruction, it will allocates a
memory location dynamically.
but, Is it possible to assign an memory address in the C program
itself?? by the user itself??
Thanks and regards,
Sethu
My question is,
>
char c;
when the compiler reads the above instruction, it will allocates a
memory location dynamically.
>
but, Is it possible to assign an memory address in the C program
itself?? by the user itself??
Thanks and regards,
Sethu
Still not clear.
Did you want to store some variable at Specific-(may be) Hardcoded
memory location. ???
--raxit sheth se*****@gmail.c om wrote:
Walter Roberson wrote:
>In article <11************ **********@f16g 2000cwb.googleg roups.com>,
<se*****@gmail. comwrote:
>i need to store a value to a particular memory location without having
a variable.
That sounds like a class assignment.
>So, how can i access a 'memory address' without using variables??
>Is it possible in C???
I'm not sure if you are asking about pointers, or if you are asking
how to store a value at a particular address location without having
to go through a lot of steps to create a variable that the linker will
happen to put at the desired location ?
no, the pointer itself pointing a memory location.
Unclear.
My question is,
char c;
when the compiler reads the above instruction, it will allocates a
memory location dynamically.
(Depending what you mean by "dynamicall y" - no; some variables are
allocated addresses statically, before the program is run, in at
least some [1] implementations .)
but, Is it possible to assign an memory address in the C program
itself?? by the user itself??
This is a /different/ (related) question. Fortunately, it has a
simple answer: No.
Standard C provides no way to bind a variable to a specific
memory address.
[1] Probably "most", but my neck isn't stretchy today.
--
Chris ".enable proofreading" Dollin
"I'm still here and I'm holding the answers" - Karnataka, /Love and Affection/ ra************@ yahoo.co.in wrote:
My question is,
char c;
when the compiler reads the above instruction, it will allocates a
memory location dynamically.
but, Is it possible to assign an memory address in the C program
itself?? by the user itself??
Thanks and regards,
Sethu
Still not clear.
Did you want to store some variable at Specific-(may be) Hardcoded
memory location. ???
--raxit sheth
absolutely. yes, i want to store some variable at a Hardcoded
memory location. ???.. is it possible?? ra************@ yahoo.co.in wrote:
My question is,
char c;
when the compiler reads the above instruction, it will allocates a
memory location dynamically.
but, Is it possible to assign an memory address in the C program
itself?? by the user itself??
Thanks and regards,
Sethu
Still not clear.
Did you want to store some variable at Specific-(may be) Hardcoded
memory location. ???
--raxit sheth
absolutely. yes, i want to store some variable at a Hardcoded
memory location. ???.. is it possible in C or C++?? ra************@ yahoo.co.in wrote:
My question is,
char c;
when the compiler reads the above instruction, it will allocates a
memory location dynamically.
but, Is it possible to assign an memory address in the C program
itself?? by the user itself??
Thanks and regards,
Sethu
Still not clear.
Did you want to store some variable at Specific-(may be) Hardcoded
memory location. ???
--raxit sheth
absolutely. yes, i want to store some variable at a Hardcoded
memory location. Is it possible in C or C++?? This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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