wxInputStream is an abstract base class which may not be used directly.

Derived from


Include files




Creates a dummy input stream.




bool CanRead() const
Returns true if some data is available in the stream right now, so that calling Read() wouldn't block.


char GetC()
Returns the first character in the input queue and removes it, blocking until it appears if necessary.


If EOF, return value is undefined and LastRead() will return 0 and not 1.


bool Eof() const
Returns true after an attempt has been made to read past the end of the stream.


In wxWidgets 2.6.x and below some streams returned Eof() when the last byte had been read rather than when an attempt had been made to read past the last byte. If you want to avoid depending on one behaviour or the other then call LastRead() to check the number of bytes actually read.


size_t LastRead() const
Returns the last number of bytes read.


char Peek()
Returns the first character in the input queue without removing it.


Blocks until something appears in the stream if necessary, if nothing ever does (i.e. EOF) LastRead() will return 0 (and the return value is undefined), otherwise LastRead() returns 1.


wxInputStream& Read(void * buffer, size_t size)
Reads the specified amount of bytes and stores the data in buffer.


The buffer absolutely needs to have at least the specified size.

Return value

This function returns a reference on the current object, so the user can test any states of the stream right away.
wxInputStream& Read(wxOutputStream& stream_out)
Reads data from the input queue and stores it in the specified output stream. The data is read until an error is raised by one of the two streams.

Return value

This function returns a reference on the current object, so the user can test any states of the stream right away.


off_t SeekI(off_t pos, wxSeekMode mode = wxFromStart)
Changes the stream current position.


Offset to seek to.
One of wxFromStart, wxFromEnd, wxFromCurrent.

Return value

The new stream position or wxInvalidOffset on error.


off_t TellI() const
Returns the current stream position.


size_t Ungetch(const char* buffer, size_t size)
This function is only useful in read mode. It is the manager of the "Write-Back" buffer. This buffer acts like a temporary buffer where data which has to be read during the next read IO call are put. This is useful when you get a big block of data which you didn't want to read: you can replace them at the top of the input queue by this way.
Be very careful about this call in connection with calling SeekI() on the same stream. Any call to SeekI() will invalidate any previous call to this method (otherwise you could SeekI() to one position, "unread" a few bytes there, SeekI() to another position and data would be either lost or corrupted).

Return value

Returns the amount of bytes saved in the Write-Back buffer.
bool Ungetch(char c)
This function acts like the previous one except that it takes only one character: it is sometimes shorter to use than the generic function.