To the compiler MinGW us informed, should serve as a literal format and compile with -Wall parameter (compiler Embarcadero / Borland does not inform us in any case, even when compiling with -w). And in the case of the example shown below (which format scanf () keeps in a separate variable - this is important), even we do not inform any warning that does not know the specifier "h" (even if you turn on the parameters -Wall -Wextra). MSVCRT not implement, for example, the specifier "h", by which we can indeed write "% HHU" (which means taking 1 byte values of type unsigned char), but the function scanf in these environments, and so fetch us the 4-byte integer (and therefore leave all specifiers "h" format and will treat it as a "% u"), which will end up overwriting an additional 3 bytes of memory placed in storage on our one byte unsigned char. int is getting short int) in each case we have an integer overflow. In cases where these unsupported specifiers reduce the size of the type to be loaded (eg. The whole essence of this error is that the functions of the family scanf getting a format specifiers which they do not support, doesn't omit a given element of the format, but forcefully trying to load it. The library is not compatible with the standard C99 (ISO 9899:1999) (and at most of the C89) and does not implement all format specifiers the scanf function (exactly the point specifiers contained in section 11 on page 358 the C99 specification).Ĭlick here to preview this page specifications
The problem lies not so much in the compiler (well, maybe a little bit-about that in a moment) as in Windowsowskiej MSVCRT library that contains an implementation of glibc, and so features such as scanf.
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