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GNU Info (gcc-300.info)Warnings and ErrorsWarning Messages and Error Messages =================================== The GNU compiler can produce two kinds of diagnostics: errors and warnings. Each kind has a different purpose: "Errors" report problems that make it impossible to compile your program. GCC reports errors with the source file name and line number where the problem is apparent. "Warnings" report other unusual conditions in your code that _may_ indicate a problem, although compilation can (and does) proceed. Warning messages also report the source file name and line number, but include the text `warning:' to distinguish them from error messages. Warnings may indicate danger points where you should check to make sure that your program really does what you intend; or the use of obsolete features; or the use of nonstandard features of GNU C or C++. Many warnings are issued only if you ask for them, with one of the `-W' options (for instance, `-Wall' requests a variety of useful warnings). GCC always tries to compile your program if possible; it never gratuitously rejects a program whose meaning is clear merely because (for instance) it fails to conform to a standard. In some cases, however, the C and C++ standards specify that certain extensions are forbidden, and a diagnostic _must_ be issued by a conforming compiler. The `-pedantic' option tells GCC to issue warnings in such cases; `-pedantic-errors' says to make them errors instead. This does not mean that _all_ non-ISO constructs get warnings or errors. Note: Options to Request or Suppress Warnings, for more detail on these and related command-line options. automatically generated by info2www version 1.2.2.9 |