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Function Documentation
void explain_message_errno_readv |
( |
char * |
message, |
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int |
message_size, |
|
|
int |
errnum, |
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int |
fildes, |
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|
const struct iovec * |
data, |
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int |
data_size |
|
) |
| |
The explain_message_errno_readv function is used to obtain an explanation of an error returned by the readv(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:
-
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. |
errnum | The 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. |
fildes | The original fildes, exactly as passed to the readv(2) system call. |
data | The original data, exactly as passed to the readv(2) system call. |
data_size | The original data_size, exactly as passed to the readv(2) system call. |
- Example:
- This function is intended to be used in a fashion similar to the following example:
ssize_t result = readv(fildes, data, data_size);
if (result < 0)
{
int err = errno;
char message[3000];
explain_message_errno_readv(message, sizeof(message), err, fildes, data,
data_size);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
- The above code example is available pre-packaged as the explain_readv_or_die function.
Definition at line 27 of file readv.c.