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Diffstat (limited to 'man3const/NULL.3const')
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diff --git a/man3const/NULL.3const b/man3const/NULL.3const deleted file mode 100644 index c88bbe0..0000000 --- a/man3const/NULL.3const +++ /dev/null @@ -1,74 +0,0 @@ -.\" Copyright (c) 2022 by Alejandro Colomar <alx@kernel.org> -.\" -.\" SPDX-License-Identifier: Linux-man-pages-copyleft -.\" -.\" -.TH NULL 3const 2023-10-31 "Linux man-pages 6.7" -.SH NAME -NULL \- null pointer constant -.SH LIBRARY -Standard C library -.RI ( libc ) -.SH SYNOPSIS -.nf -.B #include <stddef.h> -.P -.B "#define NULL ((void *) 0)" -.fi -.SH DESCRIPTION -.B NULL -represents a null pointer constant, -that is, a pointer that does not point to anything. -.SH CONFORMING TO -C99 and later; -POSIX.1-2001 and later. -.SH NOTES -The following headers also provide -.BR NULL : -.IR <locale.h> , -.IR <stdio.h> , -.IR <stdlib.h> , -.IR <string.h> , -.IR <time.h> , -.IR <unistd.h> , -and -.IR <wchar.h> . -.SH CAVEATS -It is undefined behavior to dereference a null pointer, -and that usually causes a segmentation fault in practice. -.P -It is also undefined behavior to perform pointer arithmetic on it. -.P -.I NULL \- NULL -is undefined behavior, according to ISO C, but is defined to be 0 in C++. -.P -To avoid confusing human readers of the code, -do not compare pointer variables to -.BR 0 , -and do not assign -.B 0 -to them. -Instead, always use -.BR NULL . -.P -.B NULL -shouldn't be confused with -.BR NUL , -which is an -.BR ascii (7) -character, -represented in C as -.BR \[aq]\e0\[aq] . -.SH BUGS -When it is necessary to set a pointer variable to a null pointer, -it is not enough to use -.BR memset (3) -to zero the pointer -(this is usually done when zeroing a struct that contains pointers), -since ISO C and POSIX don't guarantee that a bit pattern of all 0s -represent a null pointer. -See the EXAMPLES section in -.BR getaddrinfo (3) -for an example program that does this correctly. -.SH SEE ALSO -.BR void (3type) |