fgetpos
Gets a stream's file-position indicator.
int fgetpos(
FILE *stream,
fpos_t *pos
);
Параметры
stream
Target stream.pos
Position-indicator storage.
Возвращаемое значение
If successful, fgetpos returns 0. On failure, it returns a nonzero value and sets errno to one of the following manifest constants (defined in STDIO.H): EBADF, which means the specified stream is not a valid file pointer or is not accessible, or EINVAL, which means the stream value or the value of pos is invalid, such as if either is a null pointer. If stream or pos is a NULL pointer, the function invokes the invalid parameter handler, as described in Parameter Validation.
Заметки
The fgetpos function gets the current value of the stream argument's file-position indicator and stores it in the object pointed to by pos. The fsetpos function can later use information stored in pos to reset the stream argument's pointer to its position at the time fgetpos was called. The pos value is stored in an internal format and is intended for use only by fgetpos and fsetpos.
Требования
Function |
Required header |
|---|---|
fgetpos |
<stdio.h> |
For additional compatibility information, see Compatibility in the Introduction.
Пример
// crt_fgetpos.c
// This program uses fgetpos and fsetpos to
// return to a location in a file.
#include <stdio.h>
int main( void )
{
FILE *stream;
fpos_t pos;
char buffer[20];
if( fopen_s( &stream, "crt_fgetpos.txt", "rb" ) ) {
perror( "Trouble opening file" );
return -1;
}
// Read some data and then save the position.
fread( buffer, sizeof( char ), 8, stream );
if( fgetpos( stream, &pos ) != 0 ) {
perror( "fgetpos error" );
return -1;
}
fread( buffer, sizeof( char ), 13, stream );
printf( "after fgetpos: %.13s\n", buffer );
// Restore to old position and read data
if( fsetpos( stream, &pos ) != 0 ) {
perror( "fsetpos error" );
return -1;
}
fread( buffer, sizeof( char ), 13, stream );
printf( "after fsetpos: %.13s\n", buffer );
fclose( stream );
}
Input: crt_fgetpos.txt
fgetpos gets a stream's file-position indicator.
Output crt_fgetpos.txt
after fgetpos: gets a stream
after fsetpos: gets a stream
Эквивалент в .NET Framework
System::IO::FileStream::Position