TIFFWARNING(3tiff) LibTIFF TIFFWARNING(3tiff)
NAME
TIFFWarning - library warning interface
SYNOPSIS
#include <tiffio.h>
#include <stdarg.h>
TIFFWarning(3) char *module, const char *fmt, ...)
void TIFFWarningExt(thandle_t fd, const char *module, const char *fmt,
...)
void TIFFWarningExtR(TIFF *tif, const char *module, const char *fmt,
...)
typedef void (*TIFFWarningHandler)(const char *module, const char *fmt,
va_list ap)
typedef void (*TIFFWarningHandlerExt)(thandle_t fd, const char *module,
const char *fmt, va_list ap)
typedef int (*TIFFWarningHandlerExtR)(TIFF *tif, void *user_data, const
char *module, const char *fmt, va_list ap)
TIFFWarningHandler TIFFSetWarningHandler(TIFFWarningHandler handler)
TIFFWarningHandlerExt TIFFSetWarningHandlerExt(TIFFWarningHandlerExt
handler)
DESCRIPTION
TIFFWarning() invokes the library-wide warning handler function to
(normally) write a warning message to the stderr. The fmt parameter is
a printf() format string, and any number arguments can be supplied. The
module parameter is interpreted as a string that, if non-zero, should
be printed before the message; it typically is used to identify the
software module in which a warning is detected.
Applications that desire to capture control in the event of a warning
should use TIFFSetWarningHandler() to override the default warning
handler. A NULL (0) warning handler function may be installed to
suppress warning messages.
Two more application-specific warning handler callbacks are available,
each with different call parameters and passing parameters to the
handler. Each handler is also linked with a warning message function,
i.e. TIFFWarningExt() and TIFFWarningExtR() if the application intends
to call the handler with those extended parameters.
TIFFWarningExt() provides a file handle as parameter. Within libtiff
TIFFWarningExt() is called passing tif->tif_clientdata as fd, which
represents the TIFF file handle (file descriptor). The
application-specific and library-wide handler for TIFFWarningExt() is
setup with TIFFSetWarningHandlerExt().
TIFFWarningExtR() (introduced with libtiff 4.5) is called with its TIFF
handle and thus provides access to a per-TIFF handle (re-entrant)
warning handler. That means for different TIFF handles, different
warning handlers can be setup. This application-specific handler can be
setup when a TIFF file is opened with one of the following functions:
TIFFOpenExt(), TIFFOpenWExt(), TIFFFdOpenExt() or TIFFClientOpenExt().
Furthermore, a custom defined data structure user_data for the warning
handler can be given along.
Please refer to TIFFOpenOptions for how to setup the
application-specific handler introduced with libtiff 4.5.
NOTE
Both functions TIFFWarning() and TIFFWarningExt() each attempt to call
both handler functions if they are defined. First TIFFWarningHandler()
is called and then TIFFWarningHandlerExt(). However, TIFFWarning()
passes a "0" as a file handle to TIFFWarningHandlerExt().
TIFFWarningExtR() tries first to call the per-TIFF handle defined
warning handler. If TIFFWarningHandlerExtR() is not defined or returns
0, TIFFWarningHandler() and then TIFFWarningHandlerExt() are called.
From libtiff 4.5 onwards TIFFWarningExtR() is used within the libtiff
library.
RETURN VALUES
TIFFSetWarningHandler() and TIFFSetWarningHandlerExt() returns a
reference to the previous warning handler function.
TIFFWarningHandlerExtR() returns an integer as "stop" to control the
call of further warning handler functions within TIFFWarningExtR():
o 0: both functions TIFFWarningHandler() and TIFFWarningHandlerExt()
are called.
o non-zero: no further warning message function is called.
SEE ALSO
TIFFError(3), TIFFOpen(3), libtiff(3), printf(3)
AUTHOR
LibTIFF contributors
COPYRIGHT
1988-2025, LibTIFF contributors
4.7 September 11, 2025 TIFFWARNING(3tiff)
tiff 4.7.1 - Generated Thu Sep 25 07:22:49 CDT 2025