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authorBjörn Gustavsson <[email protected]>2015-10-01 15:41:01 +0200
committerBjörn Gustavsson <[email protected]>2016-05-04 13:04:38 +0200
commit14d72f02146b1d0aa3293eef9a823cbf0f4a4e99 (patch)
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epp: Add the -error and -warning directives
If one of several alternatives configurations are required for an Erlang module to compile, but none are available, it would be useful to give a nice error message. For example: -ifdef(CONFIG_A). %% Some code if A is true. -else. -ifdef(CONFIG_B). %% Some code if B is true. -else. -error("Neither CONFIG_A nor CONFIG_B are available"). -endif. -endif. If neither CONFIG_A nor CONFIG_B are defined, the error message will be: module.erl:10: -error("Neither CONFIG_A nor CONFIG_B are available"). That is basically the same behavior as for the #error directive in GCC. For symmetry with the -error directive, add the -warning directive to generate a compiler warning. For example: -ifdef(HAVE_COOL_FEATURE). %% Code if we have Cool Feature. -else. %% Inefficient fallback code. -warning("Using inefficient fallback"). -endif. If HAVE_COOL_FEATURE is not defined, the warning message will be: module.erl:8: Warning: -warning("Using inefficient fallback"). That is basically the same behavior as for the #warning directive in GCC. Conflicts: lib/stdlib/src/epp.erl lib/stdlib/test/epp_SUITE.erl
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