Why is p turning out const, instead of the characters pointed to?

.NET C C++ CSS DBA General HTML Java JavaScript JSP JUnit MySQL Networking Oracle Perl Perl PHP PL/SQL RSS Software QA SQL Server Struts Unix Windows XHTML XML

Home Hot About Collections Index RSS Atom Ask

Tester Developer DBA Windows JAR DLL Files Certificates RegEx Links Q&A Biotech Phones Travel FAQ Forum

Home > C

I've got the declarations
typedef char *charp;
const charp p;

Why is p turning out const, instead of the characters pointed to?

✍: Guest

typedef substitutions are not purely textual.In the declaration
const charp p;
p is const for the same reason that const int i declares i as const. The typedef'ed declaration of p does not ``look inside'' the typedef to see that there is a pointer involved.

2016-01-04, 1535👍, 0💬

What is the correct declaration of main?
What is the correct declaration of main? There are two valid declarations: int main(void) int main(int argc, char **argv) although they can be written in a variety of ways. The second parameter may be declared char *argv[] , you can use any names for the two parameters, and you can use old-style syn... 2015-12-22, 1970👍, 0💬

Why cant I pass a char to a function which expects a const char ?
Why cant I pass a char to a function which expects a const char ? You can use a pointer-to-T (for any type T) where a pointer-to-const-T is expected. However, the rule (an explicit exception) which permits slight mismatches in qualified pointer types is not applied recursively, but only at the top l... 2016-01-04, 1701👍, 0💬

I believe that declaring void main) cant fail ...
I believe that declaring void main() can't fail, since I'm calling exit instead of returning, and anyway my operating system ignores a program's exit/return status. It doesn't matter whether main returns or not, or whether anyone looks at the status; the problem is that when main is misdeclared, its... 2015-12-18, 1685👍, 0💬

If you cant modify string literals, why arent they defined as being arrays of const characters?
If you cant modify string literals, why arent they defined as being arrays of const characters? One reason is that so very much code contains lines like char *p = "Hello, world!"; which are not necessarily incorrect. These lines would suffer the diagnostic messages, but it's really any later attempt... 2016-01-06, 1684👍, 0💬

Can I declare main as void, to shut off these annoying ....
Can I declare main as void, to shut off these annoying ``main returns no value'' messages? No. main must be declared as returning an int, and as taking either zero or two arguments, of the appropriate types. If you're calling exit() but still getting warnings, you may have to insert a redundant retu... 2015-12-20, 1668👍, 0💬

But what about main's third argument, envp?
But what about main's third argument, envp? It's a non-standard (though common) extension. If you really need to access the environment in ways beyond what the standard getenv function provides, though, the global variable environ is probably a better avenue (though it's equally non-standard). 2015-12-20, 1648👍, 0💬

I dont understand why I cant use const values in initializers ....
I don't understand why I can't use const values in initializers and array dimensions, as in const int n = 5; int a[n]; The const qualifier really means ``read-only''; an object so qualified is a run-time object which cannot (normally) be assigned to. The value of a const-qualified object is therefor... 2016-01-08, 1608👍, 0💬

What is the difference between const char .....
What's the difference between const char *p, char const *p, and char * const p? The first two are interchangeable; they declare a pointer to a constant character (you can't change any pointed-to characters). char * const p declares a constant pointer to a (variable) character (i.e. you can't change ... 2016-01-06, 1608👍, 0💬

I heard that you have to include ......
I heard that you have to #include before calling printf. Why? So that a proper prototype for printf will be in scope. A compiler may use a different calling sequence for functions which accept variable-length argument lists. (It might do so if calls using variable-length argument lists were less eff... 2016-01-08, 1545👍, 0💬

.NET C C++ CSS DBA General HTML Java JavaScript JSP JUnit MySQL Networking Oracle Perl Perl PHP PL/SQL RSS Software QA SQL Server Struts Unix Windows XHTML XML

Home Hot About Collections Index RSS Atom Ask

Tester Developer DBA Windows JAR DLL Files Certificates RegEx Links Q&A Biotech Phones Travel FAQ Forum

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.