const char *explain_waitpid(int pid, int *status, int options);
const char *explain_errno_waitpid(int errnum, int pid, int *status,
int options);
void explain_message_waitpid(char *message, int message_size, int pid,
int *status, int options);
void explain_message_errno_waitpid(char *message, int message_size,
int errnum, int pid, int *status, int options);
DESCRIPTION
These functions may be used to obtain explanations for
errors returned by the waitpid(2) system call.
explain_waitpid
const char *explain_waitpid(int pid, int *status, int options);
The explain_waitpid function is
used to obtain an explanation of an error returned by the waitpid(2)
system call. The least the message will contain is the
value of strerror(errno), 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:
The original pid, exactly as passed to the waitpid(2) system call.
status
The original status, exactly as passed to the waitpid(2) system call.
options
The original options, exactly as passed to the waitpid(2) system call.
Returns:
The message explaining the error. This message buffer is
shared by all libexplain functions which do not supply a
buffer in their argument list. This will be overwritten
by the next call to any libexplain function which shares
this buffer, including other threads.
Note:
This function is not thread safe, because it
shares a return buffer across all threads, and many other
functions in this library.
explain_errno_waitpid
const char *explain_errno_waitpid(int errnum, int pid, int *status,
int options);
The explain_errno_waitpid function
is used to obtain an explanation of an error returned by
the waitpid(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.
This function is intended to be used in a fashion
similar to the following example:
if (waitpid(pid, status, options) < 0)
{
int err = errno;
fprintf(stderr, "%s\n", explain_errno_waitpid(err,
pid, status, options));
exit(EXIT_FAILURE);
}
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.
pid
The original pid, exactly as passed to the waitpid(2) system call.
status
The original status, exactly as passed to the waitpid(2) system call.
options
The original options, exactly as passed to the waitpid(2) system call.
Returns:
The message explaining the error. This message buffer is
shared by all libexplain functions which do not supply a
buffer in their argument list. This will be overwritten
by the next call to any libexplain function which shares
this buffer, including other threads.
Note:
This function is not thread safe, because it
shares a return buffer across all threads, and many other
functions in this library.
explain_message_waitpid
void explain_message_waitpid(char *message, int message_size, int pid,
int *status, int options);
The explain_message_waitpid
function may be used to obtain an explanation of an error
returned by the
waitpid(2) system call.
The least the message will contain is the value of
strerror(errno), 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:
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.
pid
The original pid, exactly as passed to the waitpid(2) system call.
status
The original status, exactly as passed to the waitpid(2) system call.
options
The original options, exactly as passed to the waitpid(2) system call.
explain_message_errno_waitpid
void explain_message_errno_waitpid(char *message, int message_size,
int errnum, int pid, int *status, int options);
The explain_message_errno_waitpid
function may be used to obtain an explanation of an error
returned by the
waitpid(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.
This function is intended to be used in a fashion
similar to the following example:
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.
pid
The original pid, exactly as passed to the waitpid(2) system call.
status
The original status, exactly as passed to the waitpid(2) system call.
options
The original options, exactly as passed to the waitpid(2) system call.