.TH ZERROR 3 libzahl
.SH NAME
zerror - Get the error that caused a jump to the jmp_buf passed to zsetup
.SH SYNOPSIS
.nf
#include <zahl.h>

enum zerror zerror(const char **\fIdesc\fP);
.fi
.SH DESCRIPTION
.B zerror
shall return the error that caused a libzahl
function to perform a long jump to the point
specified to
.BR zsetup (3).
If
.I desc
is not
.BR 0 ,
a textual description is set stored in
.IR *desc .
This string may be changed by a subsequent
call to
.BR strerror (3),
.BR perror (3),
.BR zperror (3),
and similar functions.
.P
Currently available
.B "enum zerror"
values are:
.P
.TP
.B ZERROR_ERRNO_SET
The error is stored in
.IR errno .
(The error may not be stored in
.I errno
until this function is called.)
.TP
.B ZERROR_0_POW_0
An attempt to calculate the zeroth power of zero was made.
This is on indeterminate form and cannot be calculated.
The closest matching
.I errno
value is
.BR EDOM .
.TP
.B ZERROR_0_DIV_0
An attempt to divide zero by zero was made.
This is on indeterminate form and cannot be calculated.
The closest matching
.I errno
value is
.BR EDOM .
.TP
.B ZERROR_DIV_0
An attempt to divide a non-zero value by zero was made.
This is undefined and cannot be calculated.
This occurs if a divisor or a modulator is zero, or if
zero is raised to a negative number.
The closest matching
.I errno
value is
.BR EDOM .
.TP
.B ZERROR_NEGATIVE
A function argument that must not be negative was negative.
The closest matching
.I errno
values is
.B EDOM
and
.BR EINVAL .
.SH RETURN VALUE
.B zerror
returns the error that caused libzahl a function to fail.
.SH NOTES
.I errno
is only set if
.B ZERROR_ERRNO_SET
is returned.
.SH SEE ALSO
.BR zperror (3)