What is the Eastern NULL? For example, J = char "Panorama"; This is a time when the value of p address at the Panorama Then Order p = NULL; Failure is meant indicators, the value of p is the number this time? The address is not an illegal value can. In other words, as long as the address at the proceedings should not visit p, p is NULL. So many different value can be NULL. What is the Eastern NULL? In VC, moving the mouse "NULL" above the word, it exposed the. What is the Eastern NULL? C definition which seems to (void *) 0, but it is not tightly defined, in which the book to see more complicated, I do not remember clearly. What is the Eastern NULL? Oh, thank you. I saw that it was 0 Or (void *) 0 What is the Eastern NULL? ^_^, Landlord inference very interesting, but it is wrong, let p = NULL it is a habit. You can at the other, it does not follow that a lot of value can be NULL oh. Now is the stddef.h /usr/include/linux NULL definition of the document : [code] #undef NULL #if Defined (__cplusplus) # NULL 0 #else # NULL ((void *) 0) #endif [/code] What is the Eastern NULL? ";>; Guideline is meant failure, then that the value of p is the number of times? At this point the value of p is 0, c language that provides guidelines for the visit invalid 0 ";>; Say, as long as the address at the proceedings should not visit p, p is NULL. ";>; There can be many different NULL value. P p ====== NULL then procedures should not visit at the address, not the contrary, because not many of the addresses, Oracle is zero, no other value. NULL indicator of the standard, as a special indicator variables that do not point to anything, as if a NULL indicator variables can be given a zero value to it, in order to test whether an indicator variable NULL, it could be compared with zero value. The reason is because a zero option agreement source code, on the machine itself, with indicators of the actual value may be different. Under such circumstances, the compiler is responsible for the difference between their value and internal translation conversion. -- The above paragraph from "<c and Guidelines," ;>;p96 What is the Eastern NULL? NULL is entirely (void*) 0 nothing special. For no special NULL C language syntax and semantics. See stddef.h : [code] #if Defined (__cplusplus) # NULL 0 #else # NULL ((void *) 0) #endif [/code] What is the Eastern NULL? ";>;NULL Entirely (void*) 0 nothing special. Special, but NULL ((void *) 0) is not a suitable platform for all the wording is not rigorous way, a few years ago I read articles devoted to NULL ((void *) 0), written by a foreigner, whose name I have forgotten, when c understanding of the place did not understand. I just remember NULL ((void *) 0) This is not strict. I see the ability to book any articles, so let us find out stickers. What is the Eastern NULL? In c : 1, The NULL is nothing but (void *) 0 say that is because the standard. 2, In different implementation, if p = (void *) 0, p may be not all bits zero. It seem to be Odd, but look at this, if double x = 0, x may be not all bits zero. What is the Eastern NULL? Many programs and utilities were written using UNIX on VAX computers. On this Computer, the first byte of any program is 0. Many programs written on this Bug-they use the computer contain a null pointer as a string. For example : #ifndef NULL # NULL ((char *) 0) #endif NULL Char *string; String = NULL; Printf ( "String is' %s' \n" string); This code is actually an illegal use of string. Null pointers should never be Dereferenced. On the VAX, this error causes no problems. Because of the byte Program is 0, string points to a null string. This result is due to luck, not design. On a VAX, the following result is produced : String is' ' Celerity On a computer, the first byte of the program is a 'Q'. When this program is Run on a C1200, it produces : String is' Q ' On other computers, this type of code can generate unexpected results. Many of the Utilities ported from a VAX to a Celerity exhibited the 'Q' bugs. Many of the newer compilers will now check for NULL and print : String is (null) This message does not mean that printing NULL is not an error. It means that the Error is so common that the compiler makers decided to give the programmer a Safety net. The idea is that when the error occurs, the program prints something Reasonable instead of crashing. What is the Eastern NULL? Transplantation issues. I read an article on this issue is discussed, but I can not find the original. The question is preserved, I do not see that the find. What is the Eastern NULL? 1. It says that as soon as NULL (void*) 0 is not a good idea on UNIX. But the bad idea is the TRUTH. 2. I said "no C language syntax and semantics of the special definition for NULL," which means that NULL is not a keyword of C. Most C implementations define it as a macro not anything INSIDE C. What is the Eastern NULL? --> What is the Eastern NULL? --> Your post from : --> It says as a [color=red]use the string[/color] is a null pointer bugs, but It dose not say NULL = (void *) 0 is a bugs. Right? Waitting for you post, D : Ps>; the null pointer constant is (void *) 0 now, not (char *) 0. What is the Eastern NULL? That is not a problem worth discussing. If, JohnBull and win_hate are correct. NULL C language itself, the content is not merely the habit of the people is the definition programming. # *.h The document in the language itself, the content is not constant. Ljttlf this is not what you meant? On this computer, the first byte of any program is 0. What is the Eastern NULL? In AIX Version 5 is the definition of #ifndef NULL # NULL 0 #endif What is the Eastern NULL? The symbolic constant NULL is often used in place of zero. As a mnemonic to indecate more clearly that this is a special value for a pointer. What is the Eastern NULL? Is 0 What is the Eastern NULL? "It dose not say ;>;but NULL = (void *) 0 is a bugs. Right Yes, I just said that the NULL = (void *) 0 is not a strict definition, I did not say that is Bug :) ";>;It Says that as soon as NULL (void*) 0 is not a good idea on UNIX.But the bad idea is the TRUTH. Indeed, computer science itself is the result of a compromise, such as speed and price, will ease the development of several class-inch, if it is satisfactory, the use of direct memory register so minded. The article said the C1200 (void *) 0 will be a problem, but only the transplant, some people believe that we do not mention this game. Ps : This article is "Practical c programming language inside"; What is the Eastern NULL? --> I carefully study your post. I think the main idea is "use the null pointer as a string" is illegal. elae nothing. It dose not say (voidr kilometers) is good or bad. --> Still, I waitting for this. : D [ Closed window ]