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### 4.63 `stdio_ext`,`__fbufsize`,`__fpending`,`__flbf`,`__freadable`,`__fwritable`,`__freading`,`__fwriting`—access internals of FILE structure

Synopsis

         #include <stdio.h>
         #include <stdio_ext.h>
         size_t __fbufsize(FILE *fp);
         size_t __fpending(FILE *fp);
         int __flbf(FILE *fp);
         int __freadable(FILE *fp);
         int __fwritable(FILE *fp);
         int __freading(FILE *fp);
         int __fwriting(FILE *fp);

Description
These functions provides access to the internals of the FILE structure fp.

Returns
`__fbufsize` returns the number of bytes in the buffer of stream fp.

`__fpending` returns the number of bytes in the output buffer of stream fp.

`__flbf` returns nonzero if stream fp is line-buffered, and `0` if not.

`__freadable` returns nonzero if stream fp may be read, and `0` if not.

`__fwritable` returns nonzero if stream fp may be written, and `0` if not.

`__freading` returns nonzero if stream fp if the last operation on it was a read, or if it read-only, and `0` if not.

`__fwriting` returns nonzero if stream fp if the last operation on it was a write, or if it write-only, and `0` if not.

Portability
These functions originate from Solaris and are also provided by GNU libc.

No supporting OS subroutines are required.