`clearerr_s`

Artikel
12/02/2022

Resets the error indicator for a stream. This function is a version of clearerr with security enhancements as described in Security features in the CRT.

Syntax

errno_t clearerr_s(
   FILE *stream
);

Parameters

stream
Pointer to FILE structure

Return value

Zero if successful; EINVAL if stream is NULL.

Remarks

The clearerr_s function resets the error indicator and end-of-file indicator for stream. Error indicators aren't automatically cleared; once the error indicator for a specified stream is set, operations on that stream continue to return an error value until clearerr_s, clearerr, fseek, fsetpos, or rewind is called.

If stream is NULL, the invalid parameter handler is invoked, as described in Parameter validation. If execution is allowed to continue, this function sets errno to EINVAL and returns EINVAL.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Requirements

Routine	Required header
`clearerr_s`	<stdio.h>

For more compatibility information, see Compatibility.

Example

// crt_clearerr_s.c
// This program creates an error
// on the standard input stream, then clears
// it so that future reads won't fail.

#include <stdio.h>

int main( void )
{
   int c;
   errno_t err;

   // Create an error by writing to standard input.
   putc( 'c', stdin );
   if( ferror( stdin ) )
   {
      perror( "Write error" );
      err = clearerr_s( stdin );
      if (err != 0)
      {
         abort();
      }
   }

   // See if read causes an error.
   printf( "Will input cause an error? " );
   c = getc( stdin );
   if( ferror( stdin ) )
   {
      perror( "Read error" );
      err = clearerr_s( stdin );
      if (err != 0)
      {
         abort();
      }
   }
}

Input

Output

Write error: Bad file descriptor
Will input cause an error? n

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