<cstdio>

Object containing information to control a stream

This type of object identifies a stream and contains the information needed to control it, including a pointer to its buffer, its position indicator and all its state indicators.

FILE objects are usually created by a call to either fopen or tmpfile, which both return a reference to one of these objects.
The content of a FILE object is not meant to be read from outside the functions of the cstdio library; In fact, its main purpose is to be referenced as an argument in all stream-involving functions of this library to identify the stream to be affected.
Its memory allocation is automatically performed by either fopen or tmpfile, and is the responsibility of the library to free the resources once the stream has been closed using fclose or other means.
On inclusion of the cstdio header file, three objects of type FILE * (pointer to FILE)are automatically created. These are associated with the standard input, output and error streams, and can be accessed respectivelly through the pointers stdin, stdout and stderr.

Example

#include <stdio.h>

int main()
{
   FILE * pFile;
   char buffer [100];

   pFile = fopen ("myfile.txt" , "r");
   if (pFile == NULL) perror ("Error opening file");
   else
   {
     while ( ! feof (pFile) )
     {
       fgets (buffer , 100 , pFile);
       fputs (buffer , stdout);
     }
     fclose (pFile);
   }
   return 0;
}

This example reads the content of a text file called myfile.txt and sends it to the standard output stream.

See also