setmode

Remonter à Io.h - Index

Header File

io.h

Category

Input/output Routines

Prototype

int setmode(int handle, int amode);

Description

Sets mode of an open file.

setmode sets the mode of the open file associated with handle to either binary or text. The argument amode must have a value of either O_BINARY or O_TEXT, never both. (These symbolic constants are defined in fcntl.h.)

Return Value

setmode returns the previous translation mode if successful. On error it returns -1 and sets the global variable errno to

EINVAL	Invalid argument
EBADF	Bad file number

Example

 #include <fcntl.h>
 #include <io.h>
 #include <stdio.h>
 int main (int argc, char ** argv )
 (
   FILE *fp;
   int newmode;
   long where;
   char buf[256];
   fp = fopen( argv[1], "r+" );
   if ( !fp )
   {
     printf( "Couldn't open %s\n", argv[1] );
     return -1;
   }
   newmode = setmode( fileno( fp ), O_BINARY );
   if ( newmode == -1 )
   {
     printf( "Couldn't set mode of %s\n", argv[1] );
     return -2
   }
   fp->flags |= _F_BIN;
   where = ftell( fp );
   printf ("file position: %d\n", where );
   fread( buf, 1, 1, fp );
   where = ftell ( fp );
   printf( "read %c, file position: %ld\n", *buf, where );
   fclose ( fp );
   return 0;
 }

Portability

POSIX	Win32	ANSI C	ANSI C++
	+