Technical data

Cray Standard C Extensions [5]

This chapter describes the Cray Standard C extensions to standard C. A program

that uses one or more extensions does not strictly conform to the standard. These

extensions are not available in strict conformance mode.

The following are extensions to the C standard:

• Complex data extensions (Section 5.1, page 105)

• fortran keyword (Section 5.2, page 106)

• Hexadecimal floating-point constants (Section 5.3, page 106)

5.1 Complex Data Extensions

Cray Standard C extends the complex data facilities defined by standard C. The

following are extensions for the complex data facilities:

• Imaginary constants

• Incrementing or decrementing _Complex data

The Cray Standard C compiler supports the Cray imaginary constant extension

and is defined in the <complex.h> header file. This imaginary constant has

the following form:

R is either a floating constant or an integer constant; no space or other character

can appear between R and i. If you are compiling in strict conformance mode

(-h conform), the Cray imaginary constants are not available.

The following example illustrates imaginary constants:

#include <complex.h>

double complex z1 = 1.2 + 3.4i;

double complex z2 = 5i;

The next extension to the complex data facility allows the prefix— and postfix-

increment and decrement operators to be applied to the _Complex data type.

The operations affect only the real portion of a complex number.

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