_fgetc_nolock, _fgetwc_nolock
Reads a character from a stream without locking the thread.
int _fgetc_nolock( FILE *stream ); wint_t _fgetwc_nolock( FILE *stream );
Parameters
- stream
-
Pointer to the FILE structure.
_fgetc_nolock and _fgetwc_nolock are identical to fgetc and fgetwc, respectively, except that they are not protected from interference by other threads. They might be faster because they do not incur the overhead of locking out other threads. Use these functions only in thread-safe contexts such as single-threaded applications or where the calling scope already handles thread isolation.
| Tchar.h routine | _UNICODE and _MBCS not defined | _MBCS defined | _UNICODE defined |
|---|---|---|---|
| _fgettc_nolock | _fgetc_nolock | _fgetc_nolock | _fgetwc_nolock |
| Function | Required header | Compatibility |
|---|---|---|
| _fgetc_nolock | <stdio.h> | Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 |
| _fgetwc_nolock | <stdio.h> or <wchar.h> | Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 |
For more compatibility information, see Compatibility in the Introduction.
// crt_fgetc_nolock.c
// This program uses getc to read the first
// 80 input characters (or until the end of input)
// and place them into a string named buffer.
#include <stdio.h>
#include <stdlib.h>
int main( void )
{
FILE *stream;
char buffer[81];
int i, ch;
// Open file to read line from:
if( fopen_s( &stream, "crt_fgetc_nolock.txt", "r" ) != 0 )
exit( 0 );
// Read in first 80 characters and place them in "buffer":
ch = fgetc( stream );
for( i=0; (i < 80 ) && ( feof( stream ) == 0 ); i++ )
{
buffer[i] = (char)ch;
ch = _fgetc_nolock( stream );
}
// Add null to end string
buffer[i] = '\0';
printf( "%s\n", buffer );
fclose( stream );
}
