Updated: April 19, 2023 |
Decode the last select event
#include <sys/iofunc.h> #include <sys/dispatch.h> int select_query( select_context_t *ctp, int *fd, unsigned *flags, int (**func)( select_context_t *ctp, int fd, unsigned flags, void *handle ), void **handle );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The function select_query() stores the values of the last select event, for context ctp, in fd, flags, func, and handle.
If an error occurs, the function returns -1. An error occurs if the received event doesn't belong to one of the file descriptors attached with select_attach().
#include <sys/dispatch.h> #include <stdio.h> #include <stdlib.h> #include <fcntl.h> int my_func( select_context_t *ctp, int fd, unsigned flags, void *handle ) { … } int main( int argc, char **argv ) { dispatch_t *dpp; dispatch_context_t *ctp; int fd; unsigned flag; void *handle; int (*func)( select_context_t *, int, unsigned, void * ); if( ( dpp = dispatch_create() ) == NULL ) { fprintf( stderr, "%s: Unable to allocate \ dispatch handle.\n",argv[0] ); return EXIT_FAILURE; } if( argc <= 2 || (fd = open( argv[1], O_RDWR | O_NONBLOCK )) == -1 ) { exit(0); } select_attach( dpp, NULL, fd, SELECT_FLAG_READ | SELECT_FLAG_REARM, &my_func, NULL ); ctp = dispatch_context_alloc( dpp ); … if( select_query( (select_context_t *)ctp, &fd, &flag, &func, &handle ) == -1 ) { fprintf( stderr, "Failed to decode last select event.\n"); return 1; } }
For more examples using the dispatch interface, see dispatch_create(), message_attach(), resmgr_attach(), and thread_pool_create().
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |