.TH IM_ERRORMSG 3 "22 April 1991"
.SH NAME
im_error_buffer, im_verror, im_error, im_error_clear, im_warn, im_diag,
error_exit \- handle error messages from VIPS
.SH SYNOPSIS
.B #include <vips/vips.h>

.B const char *im_error_buffer( void )

.B void im_verror( const char *domain, const char *fmt, va_list ap )

.B void im_error( const char *domain, const char *fmt, ... )

.B void im_error_system( int errno, const char *domain, const char *fmt, ... )

.B void im_error_clear()

.B void im_warn( const char *domain, const char *fmt, ... )

.B void im_diag( const char *domain, const char *fmt, ... )

.B void error_exit(  const char *fmt, ... )

.SH DESCRIPTION
.B im_error(3)
formats its arguments as printf and appends the string, with a newline, to
the error buffer. The
.B domain
argument indicates the error source and should not be marked for translation.

For example, the call:

  im_error( "mystuff", _( "bad argument %d" ), a );

might appear in the error buffer as:

  mystuff: bad argument 12

.B im_verror(3)
works exactly as
.B im_error(3)
but takes stdarg arguments.

.B im_error_system(3)
works exactly as
.B im_error(3)
but additionally will translate and append a system error code.

.B im_error_buffer(3)
returns a pointer to the start of the error buffer.

.B im_error_clear(3)
empties the error buffer.

.B error_exit(3) 
formats its arguments as printf and sends the result to the error output,
together with the contents of the error log, before terminating with an error
status.

.B im_warn(3)
works as 
.B im_error(), 
but output is sent to the list of warnings.

If an environment variable IM_WARNING exists, messages are suppressed.
Warnings should be used for non-critical recoverable errors such as values
being clipped.

.B im_diag(3)
works as 
.B im_error(), 
but output is sent to the list of diagnosic errors.

If an environment variable IM_DIAGNOSTICS exists, messages are suppressed.
Diagnostics should be used to give extra feedback about the result of the
operation.
.SH SEE ALSO
error_exit(3), im_intro(3).
.SH COPYRIGHT
.br
Birkbeck College
.SH AUTHOR
N. Dessipris \- 22/04/1991