cairo-error-status: Error handling
In RGtk2: R Bindings for Gtk 2.8.0 and Above

Description Methods and Functions Detailed Description Enums and Flags Author(s) References

Decoding cairo's status

cairoStatusToString(status)

Cairo uses a single status type to represent all kinds of errors. A status value of CAIRO_STATUS_SUCCESS represents no error and has an integer value of zero. All other status values represent an error.

Cairo's error handling is designed to be easy to use and safe. All major cairo objects retain an error status internally which can be queried anytime by the users using cairo*status() calls. In the mean time, it is safe to call all cairo functions normally even if the underlying object is in an error status. This means that no error handling code is required before or after each individual cairo function call.

CairoStatus

CairoStatus is used to indicate errors that can occur when using Cairo. In some cases it is returned directly by functions. but when using Cairo, the last error, if any, is stored in the context and can be retrieved with cairoStatus.

New entries may be added in future versions. Use cairoStatusToString to get a human-readable representation of an error message.

success: no error has occurred
no-memory: out of memory
invalid-restore: cairoRestore called without matching cairoSave
invalid-pop-group: no saved group to pop
no-current-point: no current point defined
invalid-matrix: invalid matrix (not invertible)
invalid-status: invalid value for an input CairoStatus
null-pointer: NULL pointer
invalid-string: input string not valid UTF-8
invalid-path-data: input path data not valid
read-error: error while reading from input stream
write-error: error while writing to output stream
surface-finished: target surface has been finished
surface-type-mismatch: the surface type is not appropriate for the operation
pattern-type-mismatch: the pattern type is not appropriate for the operation
invalid-content: invalid value for an input CairoContent
invalid-format: invalid value for an input CairoFormat
invalid-visual: invalid value for an input Visual*
file-not-found: file not found
invalid-dash: invalid value for a dash setting
invalid-dsc-comment: invalid value for a DSC comment (Since 1.2)
invalid-index: invalid index passed to getter (Since 1.4)
clip-not-representable: clip region not representable in desired format (Since 1.4)