Open a communications channel
struct _Ph_ctrl * PhAttach( char const *name, PhChannelParms_t const *parms );
ph
This function opens a communications channel to a Photon Manager. The channel becomes the current channel.
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A Photon channel contains:
PhAttach() doesn't create a channel; if you need to create one, call PhChannelAttach().
The name argument contains the name registered by a Photon Manager. If you pass NULL, the function uses the PHOTON environment variable. If PHOTON isn't set, the function uses /dev/photon instead.
The parms argument lets you fine-tune the resources of the channel. Passing NULL to this argument gets the channel defaults:
If you don't pass NULL for parms, you should pass a pointer to a PhChannelParms_t structure, which contains at least:
unsigned long max_q_entries; unsigned long flags;
where:
If you attach communications channels to multiple Photon managers, you'll have to keep track of which regions belong to which manager. |
A pointer to a control structure.
promiscuous_call( void ) { struct _Ph_ctrl *ph1, *ph2, *ph3; ph1 = PhAttach( NULL, NULL ); if( ph1 ) printf( "ph1 is the current channel to: " "the local Photon kernel\n" ); ph2 = PhAttach( "/dev/photon", NULL ); if( ph2 ) printf( "ph2 is the current channel to: " "the local Photon kernel\n" ); ph3 = PhAttach( "/net/darrin/dev/photon", NULL ); if( ph3 ) printf( "ph3 is the current channel to: " "the Photon kernel on node 83\n" ); if( !ph1 | !ph2 | !ph3 ) return( -1 ); PhReattach( ph1 ); printf( "ph1 is the current channel again\n" ); PhDetach( ph1 ); printf( "there is no current channel\n" ); PhReattach( ph3 ); printf( "ph3 is the current channel again\n" ); PhDetach( ph2 ); PhDetach( ph3 ); printf( "all Photon channels closed\n" ); return( 0 ); }
Photon
Safety: | |
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Interrupt handler | No |
Signal handler | No |
Thread | No |
PgSetDrawBufferSize(), PhChannelAttach(), PhDetach(), PhEventNext(), PhEventArm(), PhEventRead(), PhGetMsgSize(), PhReattach(), PtInit(), PtAppInit()