NAME

ilQueryPipe() − return information about an Image Library pipe

SYNOPSIS

unsigned int
ilQueryPipe (

ilPipe pipe,

long *pWidth,

long *pHeight,

ilImageDes *pImageDes);

DESCRIPTION

ilQueryPipe() returns the current state of an Image Library pipe as one of the following IL_PIPE_FORMING, IL_PIPE_INVALID, IL_PIPE_EMPTY, IL_PIPE_COMPLETE, or IL_PIPE_EXECUTING.  If the state is IL_PIPE_FORMING, this call also returns the currently defined image information. 

This call is useful if the results of a pipe are to be written to an image by calling ilWriteImage().  The image to be written must match the width, height and descriptor of the image in the pipe. 

pipe identifies an ilPipe structure created by ilCreatePipe(). 

*pWidth receives the currently defined image width, if the returned pipe state is IL_PIPE_FORMING and pWidth is not NULL. 

*pHeight receives the currently defined image height, if the returned pipe state is IL_PIPE_FORMING and pHeight is not NULL. 

*pImageDes receives the contents of the currently defined ilImageDes structure, if the returned pipe state is IL_PIPE_FORMING and is not NULL. 

RETURN VALUE

Upon successful completion, ilQueryPipe() returns the current state of the pipe and, if that state is IL_PIPE_FORMING, returns the currently defined image information. 

ERRORS

If the call fails, context->error receives a non-zero error code and IL_PIPE_INVALID is returned. 

EXAMPLE

The following example queries the pipe state only, and returns an error if it is not complete. 

ilPipe pipe;
.
.
.

if (ilQueryPipe(pipe, NULL, NULL, NULL) != IL_PIPE_COMPLETE)
return(IL_ERROR_PIPE_STATE);

AUTHOR

ilQueryPipe() was developed by HP. 

SEE ALSO

ilCreatePipe(3X). 

Using the Image Developer’s Kit.

Hewlett-Packard Company  —  Image Library: February, 1995