The explain_output_error_and_die function is used to print
text, and then terminate immediately. The printing is
done via the explain_output_message(3) function,
process termination is via the
explain_output_exit_failure(3) function.
fmt
The format text of the message to be printed.
See printf(3) for more information.
The explain_output_warning function is used to print a formatted
error message, including the word "warning". The printing is done
via the explain_output_message(3) function.
fmt
The format text of the message to be printed.
See printf(3) for more information.
explain_output_exit
void explain_output_exit(int status);
The explain_output_exit function is used to terminate
execution. It is executed via the registered output class,
explain_output_register(3) for how.
status
The exist status requested.
explain_output_exit_failure
void explain_output_exit_failure(void);
The explain_output_exit_failure function is used to terminate
execution, with exit status EXIT_FAILURE. It is executed via the
registered output class, see explain_output_register(3) for how.
The explain_option_hanging_indent_set function is used to cause
the output wrapping to use hanging indents. By default no hanging
indent is used, but this can sometimes obfuscate the end of one
error message and the beginning of another. A hanging indent
results in continuation lines starting with white space, similar to
RFC822 headers.
This can be set using the "hanging-indent=n"
string in the EXPLAIN_OPTIONS environment variable.
See explain(3) for more information.
Using this function will override any environment variable setting.
columns
The number of columns of hanging indent to be used. A value of
0 means no hanging indent (all lines flush with left margin).
A common value to use is 4: it doesn't consume too much of each
line, and it is a clear indent.
OUTPUT REDIRECTION
It is possible to change how and where libexplain sends its output,
and even how it calls the exit(2) function. This functionality is
used by the explain_*_or_die and explain_*_on_error functions.
By default, libexplain will wrap and print error messages on stderr,
and call the exit(2) system call to terminate execution.
Clients of the libexplain library may choose to use some message
handling facilities provided by libexplain, or they may choose to
implement their own.
The explain_output_stderr_new function may be used to create a new
dynamically allocated instance of an explain_output_t
class that writes to stderr, and exits via exit(2);
This is the default output handler.
returns
NULL on error (i.e. malloc failed), or a pointer to a new
dynamically allocated instance of the stderr class.
The explain_output_syslog_new function may be used to create a new
dynamically allocated instance of an explain_output_t
class that writes to syslog, and exits via exit(2);
The explain_output_syslog_new1 function may be used to create a new
dynamically allocated instance of an explain_output_t class that
writes to syslog, and exits via exit(2);
The syslog level to be used, see syslog(3) for a definition.
returns
NULL on error (i.e. malloc(3) failed), or a pointer to a new
dynamically allocated instance of the syslog class.
explain_output_syslog_new3
explain_output_t *explain_output_syslog_new3(int option, int facility,
int level);
The explain_output_syslog_new3 function may be used to create a new
dynamically allocated instance of an explain_output_t class that
writes to syslog, and exits via exit(2);
If you want different facilities or levels, create multiple instances.
option
The syslog option to be used, see syslog(3) for a definition.
facility
The syslog facility to be used, see syslog(3) for a definition.
level
The syslog level to be used, see syslog(3) for a definition.
returns
NULL on error (i.e. malloc(3) failed), or a pointer to a new
dynamically allocated instance of the syslog class.
explain_output_file_new
explain_output_t *explain_output_file_new(const char *filename, int append);
The explain_output_file_new function may be used to create a new
dynamically allocated instance of an explain_output_t class that
writes to a file, and exits via exit(2).
filename
The file to be opened and written to.
append
true (non-zero) if messages are to be appended to the file,
false (zero) if the file is to be replaced with new contents.
returns
NULL on error (i.e. malloc(3) or open(2) failed), or a
pointer to a new dynamically allocated instance of the syslog class.
The explain_output_tee_new function may be used to create a new
dynamically allocated instance of an explain_output_t class that
writes to two other output classes.
first
The first output class to write to.
second
The second output class to write to.
returns
NULL on error (i.e. malloc(3) failed), or a pointer to a new
dynamically allocated instance of the syslog class.
The output subsystem will "own" the first and
second objects after this call. You may not make any reference
to these pointers ever again. The output subsystem will destroy these
objects and free the memory when it feels like it.
The explain_output_register function is used to change libexplain's
default output handling facilities with something else. The NULL
pointer restores libexplain's default processing.
If no output class is registered, the default is to wrap and print
to stderr, and to exit via the exit(2) system call.
op
Pointer to the explain_output_t instance to be operated on.
The output subsystem will "own" the pointer after this call.
You may not make any reference to this pointer ever again. The output
subsystem will destroy the object and free the memory when it feels like
it.
COPYRIGHT
libexplain version 0.37
Copyright (C) 2010 Peter Miller