libexplain/message/select.c File Reference

#include <libexplain/ac/errno.h>
#include <libexplain/ac/sys/select.h>
#include <libexplain/select.h>

Go to the source code of this file.

Functions
void	explain_message_select (char *message, int message_size, int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)

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Function Documentation

void explain_message_select	(	char *	message,
		int	message_size,
		int	nfds,
		fd_set *	readfds,
		fd_set *	writefds,
		fd_set *	exceptfds,
		struct timeval *	timeout
	)

The explain_message_select function is used to obtain an explanation of an error returned by the select(2) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

This function is intended to be used in a fashion similar to the following example:

 if (select(nfds, readfds, writefds, exceptfds, timeout) < 0)
 {
     char message[3000];
     explain_message_select(message, sizeof(message), nfds, readfds,
         writefds, exceptfds, timeout);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_select_or_die function.

Parameters:

message	The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_size	The size in bytes of the location in which to store the returned message.
nfds	The original nfds, exactly as passed to the select(2) system call.
readfds	The original readfds, exactly as passed to the select(2) system call.
writefds	The original writefds, exactly as passed to the select(2) system call.
exceptfds	The original exceptfds, exactly as passed to the select(2) system call.
timeout	The original timeout, exactly as passed to the select(2) system call.

Definition at line 26 of file select.c.