GCC accepts constructs such as : float p = 0x.p5; As per C99 Standards the grammar for hexadecimal floating points is as follows : hexadecimal-floating-constant: hexadecimal-prefix hexadecimal-fractional-constant binary-exponent-part floating-suffix(opt) hexadecimal-prefix hexadecimal-digit-sequence binary-exponent-part floating-suffix(opt) hexadecimal-prefix: one of 0x 0X hexadecimal-fractional-constant: hexadecimal-digit-sequence(opt) . hexadecimal-digit-sequence hexadecimal-digit-sequence . binary-exponent-part: p signopt digit-sequence P signopt digit-sequence hexadecimal-digit-sequence: hexadecimal-digit hexadecimal-digit-sequence hexadecimal-digit floating-suffix: one of f l F L As per the grammar to my understanding, the above construct is invalid. Just wanted to know whether the support for the above construct is a GCC Extension or my understanding of the grammar is incorrect? -- View this message in context: http://old.nabble.com/GCC-Hexadecimal-Floating-point-constant-handling-tp26191496p26191496.html Sent from the gcc - Help mailing list archive at Nabble.com.