The header <errno.h> defines several macros all relating to the reporting of error conditions.
The macros required by ANSI C are:
which expand into integral constant expressions with distinct non-zero values, suitable for use in #if pre-processing directives. XGC also includes the following error definition macros:
The variable errno is declared in the library libc.a and may be set and tested at any time.
Note: The POSIX Threads library ensures each thread has a private copy of errno.
Note: Signal handlers and interrupt handlers do not have a private copy of errno.