Hi,
I want to use the C library function mkstemp. It returns a unix file
descriptor (int) to an open file. How do I convert the file descriptor to a
valid ofstream object?
Thanks,
Joe
8  9716 
"Joe" <jo*******@actcx.com> wrote in message
news:40***********************@newsreader.visi.com ... Hi,
I want to use the C library function mkstemp. It returns a unix file
descriptor (int) to an open file. How do I convert the file descriptor to
a valid ofstream object?
Thanks,
Joe
There is no portable way to do that. Look to your compiler/library docs,
some compilers (especially in Unix world) do support this.
john
"John Harrison" <jo*************@hotmail.com> wrote in message
news:bv************@ID-196037.news.uni-berlin.de...
"Joe" <jo*******@actcx.com> wrote in message
news:40***********************@newsreader.visi.com ... Hi,
I want to use the C library function mkstemp. It returns a unix file
descriptor (int) to an open file. How do I convert the file descriptor
to a valid ofstream object?
Thanks,
Joe
There is no portable way to do that. Look to your compiler/library docs,
some compilers (especially in Unix world) do support this.
john
The alternative, of course, is to write you own stream classes which can
read/write to a file descriptor. Consult a good book on the STL to find out
how to do that.
john
tom_usenet wrote: On Mon, 2 Feb 2004 09:51:58 -0600, "Joe" <jo*******@actcx.com> wrote:
Hi,
I want to use the C library function mkstemp. It returns a unix file
descriptor (int) to an open file. How do I convert the file descriptor to a
valid ofstream object?
Since unix file descriptors are non-standard (not ISO-C++ standard,
that is) it depends on your implementation. Most implementations
provide an extension that allows you to do this. e.g.
http://gcc.gnu.org/onlinedocs/libstd.../howto.html#11
Tom
C++ FAQ: http://www.parashift.com/c++-faq-lite/
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
What Tom said - however, I do remember a recent posting citing a library
called "fdstream". A google search seems to uncover some interesting links.
Joe wrote: Hi,
I want to use the C library function mkstemp. It returns a unix file
descriptor (int) to an open file. How do I convert the file descriptor to a
valid ofstream object?
Thanks,
Joe
In the GCC tool chain, the following member header occurs in fstream:
ofstream(int fd) : fstreambase(fd) { }
this means that you could write something like:
#include <fstream>
#include <stdlib.h>
#include <string.h>
int main(){
char *f_template;
f_template = new char(12);
memcpy(f_template, "/tmp/XXXXXX", 12);
int fd = mkstemp(f_template);
cout << "File Descriptor # is: " << fd << " file name = " <<
f_template <<endl;
ofstream my_temp_out(fd);
my_temp_out << "Some test text" << endl;
while(1){} // Now take a look in your temp directory for the file
//name printed from the above cout statement. If you cat it out,
//you should see the "test text".
return 0;
}
On 4 Feb 2004 00:45:00 -0800 Vamat certificate 3, s_*********@yahoo.com
(sytee) wrote: i have the following and it compile no problem
example1:
---------------------------------------------------------------------------
----class Giant{
public:
Giant();
int getHeight(){ return height; }
private:
static int height;
};
This shouldn't really compile, because you have only declared 'height'.
In addition to being declared, it needs to be defined somewhere, in some
compilation unit. The definition looks like
int Giant::height = 0;
and in effect it reserves memory for the variable and defines an initial
value (which will be 0 if no initial value is specified).
The reason that it seems to compile OK without a definition might be that
you never actually use the Giant class.
When the class is used Microsoft Visual C++ 7.1 gives this error messaqe:
error LNK2019: unresolved external symbol "public: __thiscall
Giant::Giant(void)"
(??0Giant@@QAE@XZ) referenced in function _main
---------------------------------------------------------------------------
----
i try to change the style of example1 to
example2
---------------------------------------------------------------------------
----class Giant{
public:
Giant();
int getHeight(); // here we change
private:
static int height;
};
int Giant::getHeight() {return height;}
---------------------------------------------------------------------------
----
there will be error message saying that:
test.obj : error LNK2001: unresolved external symbol "private: static
int Giant::height" (?height@Giant@@0HA)
how can i solve the problem by using back the example2 style?
to Vamat
See above.
class Giant{
public:
Giant();
int getHeight(){ return height; }
private:
static int height;
};
only above is good ? :Vamat tester This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
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