gawk: Printing Messages

1 
1 16.4.6 Printing Messages
1 ------------------------
1 
1 You can print different kinds of warning messages from your extension,
1 as described here.  Note that for these functions, you must pass in the
1 extension ID received from 'gawk' when the extension was loaded:(1)
1 
1 'void fatal(awk_ext_id_t id, const char *format, ...);'
1      Print a message and then cause 'gawk' to exit immediately.
1 
1 'void nonfatal(awk_ext_id_t id, const char *format, ...);'
1      Print a nonfatal error message.
1 
1 'void warning(awk_ext_id_t id, const char *format, ...);'
1      Print a warning message.
1 
1 'void lintwarn(awk_ext_id_t id, const char *format, ...);'
1      Print a "lint warning."  Normally this is the same as printing a
1      warning message, but if 'gawk' was invoked with '--lint=fatal',
1      then lint warnings become fatal error messages.
1 
1    All of these functions are otherwise like the C 'printf()' family of
1 functions, where the 'format' parameter is a string with literal
1 characters and formatting codes intermixed.
1 
1    ---------- Footnotes ----------
1 
1    (1) Because the API uses only ISO C 90 features, it cannot make use
1 of the ISO C 99 variadic macro feature to hide that parameter.  More's
1 the pity.
1