FILE data type

Applications Programming
1

Hi all,
Can anyone tell me a little about the datatype FILE, which represents stream. What does its structure look like, and in which header file is it defined and so on...

Ex :

      FILE *fp ;
      fp = fopen("filename", "w") ;
2

it is in stdio.h


typedef struct {
        unsigned char   *_ptr;
        int     _cnt;
        unsigned char   *_base;
        unsigned char   *_bufendp;
        short   _flag;
        short   _file;
        int     __stdioid;
        char    *__newbase;
#ifdef _THREAD_SAFE
        void *_lock;
#else
        long    _unused[1];
#endif
#ifdef __64BIT__
        long    _unused1[4];
#endif /* __64BIT__ */
} FILE;
3

thanks for the answer, but when I go in the stdio.h file, there's no such definition. Instead, there's a statement like :

using std::FILE ;

where is std?

4

The standard C++ namespace.

5

yes, i know, it's c++ namespace, but how can I can and view what is inside the namespace, where is that std file?

6

hi
the std-namespace must also be defined somewhere.
in solaris stdio.h includes iso/stdio_iso.h where the c++-namespace std is defined.
the gnu c-compiler (gcc) has the flag -E which only applies the c-preprocessor and writes the generated text to the output. preprocessor output is described in http://www.delorie.com/gnu/docs/gcc/cpp_47.html
whicth this output you can see all macro-definitions expanded and from where they come from. perhaps other compilers have similar options.
guenter

7

if not solaris,
try /usr/include/stdio.h
this path is common on most Linx distro's