libexplain  1.4.D001
Functions
libexplain/message/errno/adjtime.c File Reference
#include <libexplain/buffer/errno/adjtime.h>
#include <libexplain/adjtime.h>

Go to the source code of this file.

Functions

void explain_message_errno_adjtime (char *message, int message_size, int errnum, const struct timeval *delta, struct timeval *olddelta)

Function Documentation

void explain_message_errno_adjtime ( char *  message,
int  message_size,
int  errnum,
const struct timeval *  delta,
struct timeval *  olddelta 
)

The explain_message_errno_adjtime function is used to obtain an explanation of an error returned by the adjtime(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.

Parameters:
messageThe location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_sizeThe size in bytes of the location in which to store the returned message.
errnumThe error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.
deltaThe original delta, exactly as passed to the adjtime(2) system call.
olddeltaThe original olddelta, exactly as passed to the adjtime(2) system call.
Example:
This function is intended to be used in a fashion similar to the following example:
 if (adjtime(delta, olddelta) < 0)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_adjtime(message, sizeof(message), err, delta,
         olddelta);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }
The above code example is available pre-packaged as the explain_adjtime_or_die function.

Definition at line 24 of file adjtime.c.