The <errno.h>
header provides the global error code variable errno
.
Global Variables
errno Variable
Purpose
Declared In
posix/errno.h
Prototype
extern int errno
Comments
The errno
variable is used by many functions to return error values. The value of errno
is defined only after a call to a function for which it is explicitly stated to be set and until it is changed by the next function call. The value of errno
should only be examined when it is indicated to be valid by a function's return value. Programs should obtain the definition of errno
by the inclusion of <errno.h
>. It is unspecified whether errno
is a macro or an identifier declared with external linkage.
The errno
variable has a value of zero (0) at the beginning. If an error occurs, then this variable is given the value of the error number. In some cases, the behavior of the math library with regard to errno
is implementation defined.
Nothing in the <errno.h
> header is specific to Palm OS®. The specific numeric values associated with the error names are not portable and should be treated as opaque by applications.