Search results
Results from the WOW.Com Content Network
The usual practice is to collect extern declarations of variables and functions in a separate file, historically called a header, that is included by #include at the front of each source file. The suffix .h is conventional for header names.
A convenient way is to define the inline functions in header files and create one .c file per function, containing an extern inline declaration for it and including the respective header file with the definition. It does not matter whether the declaration is before or after the include.
A common practice for header files to maintain both C and C++ compatibility is to make its declaration be extern "C" for the scope of the header: [21] /* Header file foo.h */ #ifdef __cplusplus /* If this is a C++ compiler, use C linkage */ extern "C" { #endif /* These functions get C linkage */ void foo (); struct bar { /* ... */ }; #ifdef ...
This typically occurs if a header file is included twice by the same source file without appropriate header guards. class C {}; // first definition of C class C {}; // error, second definition of C In the following, forming a pointer to S or defining a function taking a reference to S are examples of legal constructs, because they do not ...
Such extern declarations are often placed in a shared header file, since it is common practice for all .c files in a project to include at least one .h file: the standard header file errno.h is an example, making the errno variable accessible to all modules in a project.
The application programming interface (API) of the C standard library is declared in a number of header files. Each header file contains one or more function declarations, data type definitions, and macros. After a long period of stability, three new header files (iso646.h, wchar.h, and wctype.h) were added with Normative Addendum 1 (NA1), an ...
In the C and C++ programming languages, unistd.h is the name of the header file that provides access to the POSIX operating system API. [1] It is defined by the POSIX.1 standard, the base of the Single Unix Specification, and should therefore be available in any POSIX-compliant operating system and compiler.
The C++ Standard Library includes in the header file functional many different predefined function objects, including arithmetic operations (plus, minus, multiplies, divides, modulus, and negate), comparisons (equal_to, not_equal_to, greater, less, greater_equal, and less_equal), and logical operations (logical_and, logical_or, and logical_not).