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erl_error(3erl) | C Library Functions | erl_error(3erl) |
NAME¶
erl_error - Error print routines.DESCRIPTION¶
This module contains some error printing routines taken from "Advanced Programming in the UNIX Environment" by W. Richard Stevens. These functions are all called in the same manner as printf(), that is, with a string containing format specifiers followed by a list of corresponding arguments. All output from these functions is to stderr.EXPORTS¶
void erl_err_msg(FormatStr, ... )
Types:
const char *FormatStr;
The message provided by the caller is printed. This function is simply a wrapper
for fprintf().
void erl_err_quit(FormatStr, ... )
Types:
const char *FormatStr;
Use this function when a fatal error has occurred that is not because of a
system call. The message provided by the caller is printed and the process
terminates with exit value 1. This function does not return.
void erl_err_ret(FormatStr, ... )
Types:
const char *FormatStr;
Use this function after a failed system call. The message provided by the caller
is printed followed by a string describing the reason for failure.
void erl_err_sys(FormatStr, ... )
Types:
const char *FormatStr;
Use this function after a failed system call. The message provided by the caller
is printed followed by a string describing the reason for failure, and the
process terminates with exit value 1. This function does not
return.
ERROR REPORTING¶
Most functions in Erl_Interface report failures to the caller by returning some otherwise meaningless value (typically NULL or a negative number). As this only tells you that things did not go well, examine the error code in erl_errno if you want to find out more about the failure.EXPORTS¶
volatile int erl_errno
erl_errno is initially (at program startup) zero and is then set by many
Erl_Interface functions on failure to a non-zero error code to indicate
what kind of error it encountered. A successful function call can change
erl_errno (by calling some other function that fails), but no function
does never set it to zero. This means that you cannot use erl_errno to
see if a function call failed. Instead, each function reports failure
in its own way (usually by returning a negative number or NULL), in
which case you can examine erl_errno for details.
erl_errno uses the error codes defined in your system's
<errno.h>.
Note:
erl_errno is a "modifiable lvalue" (just like ISO C defines
errno to be) rather than a variable. This means it can be implemented
as a macro (expanding to, for example, *_erl_errno()). For reasons of
thread safety (or task safety), this is exactly what we do on most platforms.
erl_interface 3.9.2 | Ericsson AB |