GLGETEROR(3G) GLGETEROR(3G)
NAME
glGetError - return error information
C SPECIFICATION
GLenum glGetError( void )
DESCRIPTION
glGetError returns the value of the error flag. Each detectable error
is assigned a numeric code and symbolic name. When an error occurs,
the error flag is set to the appropriate error code value. No other
errors are recorded until glGetError is called, the error code is
returned, and the flag is reset to GLNOEROR. If a call to
glGetError returns GLNOEROR, there has been no detectable error
since the last call to glGetError, or since the GL was initialized.
To allow for distributed implementations, there may be several error
flags. If any single error flag has recorded an error, the value of
that flag is returned and that flag is reset to GLNOEROR when
glGetError is called. If more than one flag has recorded an error,
glGetError returns and clears an arbitrary error flag value. Thus,
glGetError should always be called in a loop, until it returns
GLNOEROR, if all error flags are to be reset.
Initially, all error flags are set to GLNOEROR.
The following errors are currently defined:
GLNOEROR No error has been recorded. The value of
this symbolic constant is guaranteed to
be 0.
GLINVALIDENUM An unacceptable value is specified for an
enumerated argument. The offending com-
mand is ignored, and has no other side
effect than to set the error flag.
GLINVALIDVALUE A numeric argument is out of range. The
offending command is ignored, and has no
other side effect than to set the error
flag.
GLINVALIDOPERATION The specified operation is not allowed in
the current state. The offending command
is ignored, and has no other side effect
than to set the error flag.
GLSTACKOVERFLOW This command would cause a stack over-
flow. The offending command is ignored,
and has no other side effect than to set
the error flag.
GLSTACKUNDERFLOW This command would cause a stack under-
flow. The offending command is ignored,
and has no other side effect than to set
the error flag.
GLOUTOFMEMORY There is not enough memory left to exe-
cute the command. The state of the GL is
undefined, except for the state of the
error flags, after this error is
recorded.
GLTABLETOLARGE The specified table exceeds the implemen-
tation's maximum supported table size.
The offending command is ignored, and has
no other side effect than to set the
error flag.
When an error flag is set, results of a GL operation are undefined only
if GLOUTOFMEMORY has occurred. In all other cases, the command gen-
erating the error is ignored and has no effect on the GL state or frame
buffer contents. If the generating command returns a value, it returns
0. If glGetError itself generates an error, it returns 0.
NOTES
GLTABLETOLARGE was introduced in GL version 1.2.
ERORS
GLINVALIDOPERATION is generated if glGetError is executed between the
execution of glBegin and the corresponding execution of glEnd. In this
case glGetError returns 0.
GLGETEROR(3G)
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