*ptr = 'hello world";
if we try to modify the content the result is undefined when i worked with gcc in unix.
But i can modify the content in Turbo c. How it worked i got confussed.
harish9
-3
Newbie Poster
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Jump to PostWhen you have a pointer defined like so
char *ptr = "hello world";It creates a read only character pointer. If you require a char array that's writable then use.
char ptr[] = "hello world";
Jump to PostThis is one of those things that the standards allow implementations to "do their own thing" on. A string literal may (or may not) be in read-only memory as a constant. So, gerard4143 is absolutely correct if you want to modify the contents of the string in a platform-neutral manner. …
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gerard4143
371
Nearly a Posting Maven
When you have a pointer defined like so
char *ptr = "hello world";It creates a read only character pointer. If you require a char array that's writable then use.
char ptr[] = "hello world";
rubberman
1,355
Nearly a Posting Virtuoso
Featured Poster
This is one of those things that the standards allow implementations to "do their own thing" on. A string literal may (or may not) be in read-only memory as a constant. So, gerard4143 is absolutely correct if you want to modify the contents of the string in a platform-neutral manner. Neither gcc nor Turbo are breaking the rules. It's just that the rules are flexible in such cases. Caveat Programmer! :-)
gerard4143
commented:
Didn't know that, thanks for the pointer.
+5
harish9
-3
Newbie Poster
thanku for ur information. I know it is stored in read only memory and i also know that we can't alter a value but how it worked in Turbo C thats my question.
gerard4143
371
Nearly a Posting Maven
thanku for ur information. I know it is stored in read only memory and i also know that we can't alter a value but how it worked in Turbo C thats my question.
Why it worked in Turbo C, read Rubberman's post.
Narue
5,707
Bad Cop
Team Colleague
if we try to modify the content the result is undefined when i worked with gcc in unix.
Correction: the result is always undefined, regardless of compiler. Whether it "works" or not depends on how the compiler implements string literals and enforces modification. Even if it "works", you could still be creating a subtle error down the line.
The lesson to be learned is don't rely on undefined behavior.
quynyth
0
Newbie Poster
I am not familiar this topic of C language but I have backgrounds on some basic from the language. I hope you can help me with this topic.
gerard4143
371
Nearly a Posting Maven
I am not familiar this topic of C language but I have backgrounds on some basic from the language. I hope you can help me with this topic.
What is this?
rubberman
1,355
Nearly a Posting Virtuoso
Featured Poster
What is this?
Trolling I think.
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