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How to get the sizeof char pointer
Post 302322322 by fpmurphy on Wednesday 3rd of June 2009 10:49:09 AM
06-03-2009
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10 More Discussions You Might Find Interesting
1. Programming
we know that sizeof never returns zero when used with structure
then why in this case it is returning zero
struct foo
{
char c;
};
void main()
{
struct foo f;
cout<<sizeof(f);
}
i am working on solaris 5.8
isn't the above function should return the size of empty structure (7 Replies)
Discussion started by: ramneek
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2. Programming
Hi,
char *s="yamaha";
cout<<s<<endl;
int *p;
int i=10;
p=&i;
cout<<p<<endl;
1) For the 1st "cout" we will get "yamaha" as output. That is we are getting "content of the address" for cout<<s.
2) But for integer "cout<<p" we are getting the "address only".
Please clarify how we are... (2 Replies)
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3. Programming
Hello,
I'm trying to write a method which will return the extension of a file given the file's name, e.g. test.txt should return txt. I'm using C so am limited to char pointers and arrays. Here is the code as I have it:
char* getext(char *file)
{
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int i, j;... (5 Replies)
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4. Programming
If one wants to get a start address of a array or a string or a block of memory via a function, there are at least two methods to achieve it:
(1) one is to pass a pointer-to-pointer parameter, like:
int my_malloc(int size, char **pmem)
{
*pmem=(char *)malloc(size);
if(*pmem==NULL)... (11 Replies)
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5. Programming
Hi All,
is it possible to find out the size of an array of structures ( without using 'sizeof' operator). The condition is we have the array of structure instant but we are not aware of the elements inside the structure.
Can someone help me out?
Thanks in advance. (18 Replies)
Discussion started by: rvan
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6. Programming
Hi,
There are some bewildering sizeof() questions I have in my mind. Could anyone shed some light on this?
int main() {
printf("%d\n", sizeof(main)); // Ans: 1
}
That is, the sizeof() a function identifier though it is treated internally as a pointer gives 1 byte always, why?
... (5 Replies)
Discussion started by: royalibrahim
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7. Programming
Hi,
I have defined the class and call the sizeof(object to class) to get the size.
# include <iostream>
# include <iomanip>
using namespace std;
class sample
{
private:
int i;
float j;
char k;
public:
sample()
{
} (2 Replies)
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8. Programming
i have an array like
#define NUM 8
....
new_socket_fd = accept(socket_fd, (struct sockaddr *) &cli_addr, &client_length);
char *items = {"one", "two", "three", "four", "five", "six", "seven", "eight"};
char *item_name_length = {"3", "3", "5", "4", "4", "3", "5", "5"};
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9. Programming
Ignoring other considerations for a moment and in general ...
Would there be a difference in result (dot oh or execution) of:
A.
strncpy( a, b, sizeof(a) );
vs.
B.
c = sizeof(a);
strncpy( a, b, c );
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10. Programming
I am passing a char* to the function "reverse" and when I execute it with gdb I get:
Program received signal SIGSEGV, Segmentation fault.
0x000000000040083b in reverse (s=0x400b2b "hello") at pointersExample.c:72
72 *q = *p;
Attached is the source code.
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LEARN ABOUT SUNOS
confstr
confstr(3C) Standard C Library Functions confstr(3C) NAME
confstr - get configurable variables SYNOPSIS
#include <unistd.h> size_t confstr(int name, char *buf, size_t len); DESCRIPTION
The confstr() function provides a method for applications to get configuration-defined string values. Its use and purpose are similar to the sysconf(3C) function, but it is used where string values rather than numeric values are returned. The name argument represents the system variable to be queried. If len is not 0, and if name has a configuration-defined value, confstr() copies that value into the len-byte buffer pointed to by buf. If the string to be returned is longer than len bytes, including the terminating null, then confstr() truncates the string to len-1 bytes and null-terminates the result. The application can detect that the string was truncated by comparing the value returned by confstr() with len. If len is 0, confstr() still returns the integer value as defined below, but does not return the string. The confstr() function supports the following values for name, defined in <unistd.h>, for both SPARC and x86: _CS_LFS64_CFLAGS If _LFS64_LARGEFILE is defined in <unistd.h>, this value is the set of initial options to be given to the cc and c89 utilities to build an application using the Large File Summit transitional compilation environment (see lfcompile64(5)). _CS_LFS64_LDFLAGS If _LFS64_LARGEFILE is defined in <unistd.h>, this value is the set of final options to be given to the cc and c89 utilities to build an application using the Large File Summit transitional compilation environment (see lfcompile64(5)). _CS_LFS64_LIBS If _LFS64_LARGEFILE is defined in <unistd.h>, this value is the set of libraries to be given to the cc and c89 utilities to build an application using the Large File Summit transitional compilation environment (see lfcompile64(5)). _CS_LFS64_LINTFLAGS If _LFS64_LARGEFILE is defined in <unistd.h>, this value is the set of options to be given to the lint utility to check application source using the Large File Summit transitional compilation environment (see lfcompile64(5)). _CS_LFS_CFLAGS If _LFS_LARGEFILE is defined in <unistd.h>, this value is the set of initial options to be given to the cc and c89 utilities to build an application using the Large File Summit large file compilation environment for 32-bit applications (see lfcompile(5)). _CS_LFS_LDFLAGS If _LFS_LARGEFILE is defined in <unistd.h>, this value is the set of final options to be given to the cc and c89 utilities to build an application using the Large File Summit large file compilation environment for 32-bit applications (see lfcompile(5)). _CS_LFS_LIBS If _LFS_LARGEFILE is defined in <unistd.h>, this value is the set of libraries to be given to the cc and c89 utilities to build an application using the Large File Summit large file compilation environment for 32-bit applications (see lfcompile(5)). _CS_LFS_LINTFLAGS If _LFS_LARGEFILE is defined in <unistd.h>, this value is the set of options to be given to the lint utility to check application source using the Large File Summit large file compilation environment for 32-bit applications (see lfcompile(5)). _CS_PATH If the ISO POSIX.2 standard is supported, this is the value for the PATH environment variable that finds all standard utilities. Oth- erwise the meaning of this value is unspecified. _CS_POSIX_V6_ILP32_OFF32_CFLAGS If sysconf(_SC_V6_ILP32_OFF32) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the c99 utility to build an application using a programming model with 32-bit int, long, pointer, and off_t types. _CS_POSIX_V6_ILP32_OFF32_LDFLAGS If sysconf(_SC_V6_ILP32_OFF32) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the c99 utility to build an application using a programming model with 32-bit int, long, pointer, and off_t types. _CS_POSIX_V6_ILP32_OFF32_LIBS If sysconf(_SC_V6_ILP32_OFF32) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the c99 utility to build an application using a programming model with 32-bit int, long, pointer, and off_t types. _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS If sysconf(_SC_V6_ILP32_OFFBIG) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the c99 utility to build an application using a programming model with 32-bit int, long, and pointer types, and an off_t type using at least 64 bits. _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS If sysconf(_SC_V6_ILP32_OFFBIG) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the c99 utility to build an application using a programming model with 32-bit int, long, and pointer types, and an off_t type using at least 64 bits. _CS_POSIX_V6_ILP32_OFFBIG_LIBS If sysconf(_SC_V6_ILP32_OFFBIG) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the c99 utility to build an application using a programming model with 32-bit int, long, and pointer types, and an off_t type using at least 64 bits. _CS_POSIX_V6_LP64_OFF64_CFLAGS If sysconf(_SC_V6_LP64_OFF64) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the c99 utility to build an application using a programming model with 64-bit int, long, pointer, and off_t types. _CS_POSIX_V6_LP64_OFF64_LDFLAGS If sysconf(_SC_V6_LP64_OFF64) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the c99 utility to build an application using a programming model with 64-bit int, long, pointer, and off_t types. _CS_POSIX_V6_LP64_OFF64_LIBS If sysconf(_SC_V6_LP64_OFF64) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the c99 utility to build an application using a programming model with 64-bit int, long, pointer, and off_t types. _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS If sysconf(_SC_V6_LPBIG_OFFBIG) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the c99 utility to build an application using a programming model with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits. _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS If sysconf(_SC_V6_LPBIG_OFFBIG) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the c99 utility to build an application using a programming model with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits. _CS_POSIX_V6_LPBIG_OFFBIG_LIBS If sysconf(_SC_V6_LPBIG_OFFBIG) returns -1, the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the c99 utility to build an application using a programming model with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits. _CS_POSIX_V6_WIDTH_RESTRICTED_ENVS This value is a <newline>-separated list of names of programming environments supported by the implementation in which the widths of the blksize_t, cc_t, mode_t, nfds_t, pid_t, ptrdiff_t, size_t, speed_t, ssize_t, suseconds_t, tcflag_t, useconds_t, wchar_t, and wint_t types are no greater than the width of type long. _CS_XBS5_ILP32_OFF32_CFLAGS If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the cc and c89 utilities to build an application using a programming model with 32-bit int, long, pointer, and off_t types. _CS_XBS5_ILP32_OFF32_LDFLAGS If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the cc and c89 utilities to build an application using a programming model with 32-bit int, long, pointer, and off_t types. _CS_XBS5_ILP32_OFF32_LIBS If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the cc and c89 utilities to build an application using a programming model with 32-bit int, long, pointer, and off_t types. _CS_XBS5_ILP32_OFF32_LINTFLAGS If sysconf(_SC_XBS5_ILP32_OFF32) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of options to be given to the lint utility to check application source using a programming model with 32-bit int, long, pointer, and off_t types. _CS_XBS5_ILP32_OFFBIG_CFLAGS If sysconf(_SC_XBS5_ILP32_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the cc and c89 utilities to build an application using a programming model with 32-bit int, long, and pointer types, and an off_t type using at least 64 bits. _CS_XBS5_ILP32_OFFBIG_LDFLAGS If sysconf(SC_XBS5_ILP32_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the cc and c89 utilities to build an application using a programming model with 32-bit int, long, and pointer types, and an off_t type using at least 64 bits. _CS_XBS5_ILP32_OFFBIG_LIBS If sysconf(_SC_XBS5_ILP32_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the cc and c89 utilities to build an application using a programming model with 32-bit int, long, and pointer types, and an off_t type using at least 64 bits. _CS_XBS5_ILP32_OFFBIG_LINTFLAGS If sysconf(_SC_XBS5_ILP32_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of options to be given to the lint utility to check an application using a programming model with 32-bit int, long, and pointer types, and an off_t type using at least 64 bits. The confstr() function supports the following values for name, defined in <unistd.h>, for SPARC only: _CS_XBS5_LP64_OFF64_CFLAGS If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the cc and c89 utilities to build an application using a programming model with 64-bit int, long, pointer, and off_t types. _CS_XBS5_LP64_OFF64_LDFLAGS If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the cc and c89 utilities to build an application using a programming model with 64-bit int, long, pointer, and off_t types. _CS_XBS5_LP64_OFF64_LIBS If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the cc and c89 utilities to build an application using a programming model with 64-bit int, long, pointer, and off_t types. _CS_XBS5_LP64_OFF64_LINTFLAGS If sysconf(_SC_XBS5_LP64_OFF64) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of options to be given to the lint utility to check application source using a programming model with 64-bit int, long, pointer, and off_t types. _CS_XBS5_LPBIG_OFFBIG_CFLAGS If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of initial options to be given to the cc and c89 utilities to build an application using a programming model with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits. _CS_XBS5_LPBIG_OFFBIG_LDFLAGS If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of final options to be given to the cc and c89 utilities to build an application using a programming model with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits. _CS_XBS5_LPBIG_OFFBIG_LIBS If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of libraries to be given to the cc and c89 utilities to build an application using a programming model with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits. _CS_XBS5_LPBIG_OFFBIG_LINTFLAGS If sysconf(_SC_XBS5_LPBIG_OFFBIG) returns -1 the meaning of this value is unspecified. Otherwise, this value is the set of options to be given to the lint utility to check application source using a programming model with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits. RETURN VALUES
If name has a configuration-defined value, the confstr() function returns the size of buffer that would be needed to hold the entire con- figuration-defined value. If this return value is greater than len, the string returned in buf is truncated. If name is invalid, confstr() returns 0 and sets errno to indicate the error. If name does not have a configuration-defined value, confstr() returns 0 and leaves errno unchanged. ERRORS
The confstr() function will fail if: EINVAL The value of the name argument is invalid. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |Mt-Safe | +-----------------------------+-----------------------------+ SEE ALSO
pathconf(2), sysconf(3C), attributes(5), lfcompile(5), lfcompile64(5), standards(5) SunOS 5.10 15 Dec 2003 confstr(3C)