_set_crt_msg_handle - Change Run-Time Message Output Destination

Syntax

#include <stdio.h>
int _set_crt_msg_handle(int fh);

set_crt_msg_handle changes the file handle to which run-time messages are sent, which is usually file handle 2, to fh. Run-time messages include exception handling messages and output from debug memory management routines.
Use _set_crt_msg_handle to trap run-time message output in applications where handle 2 is not defined, such as Presentation Manager applications.
The file handle fh must be a writable file or pipe handle. Set fh only for the current library environment.

set_crt_msg_handle returns the handle to be used for run-time message output. If an handle that is not valid is passed as an argument, it is ignored and no change takes place.

This example causes an exception by dereferencing a null pointer and uses _set_crt_msg_handle to send the exception messages to the file _scmhdl.out.

#include <sys\stat.h>
#include <io.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
   int   fh;
   char  *p = NULL;

   if (-1 == (fh = open("_scmhdl.out", O_CREAT|O_TRUNC|O_RDWR,
                        S_IREAD|S_IWRITE))) {
      perror("Unable to open the file _scmhdl.out.");
      exit(EXIT_FAILURE);
   }
   /* change file handle where messages are sent */
   if (fh != _set_crt_msg_handle(fh)) {
      perror("Could not change massage output handle.");
      exit(EXIT_FAILURE);
   }
   *p = 'x';          /* cause an exception, output should be in _scmhdl.out */
   if (-1 == close(fh)) {
      perror("Unable to close _scmhdl.out.");
      exit(EXIT_FAILURE);
   }
   return 0;

   /****************************************************************************
      Running this program would cause an exception to occur,
      the file _scmhdl.out should contain the exception messages similar to :

      Exception = c0000005 occurred at EIP = 10068.
   ****************************************************************************/
}

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